| 函数名: sbrk
功 能: 改变数据段空间位置
用 法: char *sbrk(int incr);
程序例:
#include
#include
int main(void)
{
printf("Changing allocation with sbrk()\n");
printf("Before sbrk() call: %lu bytes free\n",
(unsigned long) coreleft());
sbrk(1000);
printf(" After sbrk() call: %lu bytes free\n",
(unsigned long) coreleft());
return 0;
}
函数名: scanf
功 能: 执行格式化输入
用 法: int scanf(char *format[,argument,...]);
程序例:
#include
#include
int main(void)
{
char label[20];
char name[20];
int entries = 0;
int loop, age;
double salary;
struct Entry_struct
{
char name[20];
int age;
float salary;
} entry[20];
/* Input a label as a string of characters restricting to 20 characters */
printf("\n\nPlease enter a label for the chart: ");
scanf("%20s", label);
fflush(stdin); /* flush the input stream in case of bad input */
/* Input number of entries as an integer */
printf("How many entries will there be? (less than 20) ");
scanf("%d", &entries);
fflush(stdin); /* flush the input stream in case of bad input */
/* input a name restricting input to only letters upper or lower case */
for (loop=0;loop
#include
int main(void)
{
char *p;
/* Looks for TLINK and returns a pointer
to the path */
p = searchpath("TLINK.EXE");
printf("Search for TLINK.EXE : %s\n", p);
/* Looks for non-existent file */
p = searchpath("NOTEXIST.FIL");
printf("Search for NOTEXIST.FIL : %s\n", p);
return 0;
}
函数名: sector
功 能: 画并填充椭圆扇区
用 法: void far sector(int x, int y, int stangle, int endangle);
程序例:
#include
#include
#include
#include
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy, i;
int stangle = 45, endangle = 135;
int xrad = 100, yrad = 50;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
/* loop through the fill patterns */
for (i=EMPTY_FILL; i
#include
int main(void)
{
struct SREGS segs;
segread(&segs);
printf("Current segment register settings\n\n");
printf("CS: %X DS: %X\n", segs.cs, segs.ds);
printf("ES: %X SS: %X\n", segs.es, segs.ss);
return 0;
}
函数名: setactivepage
功 能: 设置图形输出活动页
用 法: void far setactivepage(int pagenum);
程序例:
#include
#include
#include
#include
int main(void)
{
/* select a driver and mode that supports */
/* multiple pages. */
int gdriver = EGA, gmode = EGAHI, errorcode;
int x, y, ht;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
x = getmaxx() / 2;
y = getmaxy() / 2;
ht = textheight("W");
/* select the off screen page for drawing */
setactivepage(1);
/* draw a line on page #1 */
line(0, 0, getmaxx(), getmaxy());
/* output a message on page #1 */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "This is page #1:");
outtextxy(x, y+ht, "Press any key to halt:");
/* select drawing to page #0 */
setactivepage(0);
/* output a message on page #0 */
outtextxy(x, y, "This is page #0.");
outtextxy(x, y+ht, "Press any key to view page #1:");
getch();
/* select page #1 as the visible page */
setvisualpage(1);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setallpallette
功 能: 按指定方式改变所有的调色板颜色
用 法: void far setallpallette(struct palette, far *pallette);
程序例:
#include
#include
#include
#include
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
struct palettetype pal;
int color, maxcolor, ht;
int y = 10;
char msg[80];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
maxcolor = getmaxcolor();
ht = 2 * textheight("W");
/* grab a copy of the palette */
getpalette(&pal);
/* display the default palette colors */
for (color=1; color<=maxcolor; color++)
{
setcolor(color);
sprintf(msg, "Color: %d", color);
outtextxy(1, y, msg);
y += ht;
}
/* wait for a key */
getch();
/* black out the colors one by one */
for (color=1; color<=maxcolor; color++)
{
setpalette(color, BLACK);
getch();
}
/* restore the palette colors */
setallpalette(&pal);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setaspectratio
功 能: 设置图形纵横比
用 法: void far setaspectratio(int xasp, int yasp);
程序例:
#include
#include
#include
#include
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int xasp, yasp, midx, midy;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
setcolor(getmaxcolor());
/* get current aspect ratio settings */
getaspectratio(&xasp, &yasp);
/* draw normal circle */
circle(midx, midy, 100);
getch();
/* claer the screen */
cleardevice();
/* adjust the aspect for a wide circle */
setaspectratio(xasp/2, yasp);
circle(midx, midy, 100);
getch();
/* adjust the aspect for a narrow circle */
cleardevice();
setaspectratio(xasp, yasp/2);
circle(midx, midy, 100);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setbkcolor
功 能: 用调色板设置当前背景颜色
用 法: void far setbkcolor(int color);
程序例:
#include
#include
#include
#include
int main(void)
{
/* select a driver and mode that supports */
/* multiple background colors. */
int gdriver = EGA, gmode = EGAHI, errorcode;
int bkcol, maxcolor, x, y;
char msg[80];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
/* maximum color index supported */
maxcolor = getmaxcolor();
/* for centering text messages */
settextjustify(CENTER_TEXT, CENTER_TEXT);
x = getmaxx() / 2;
y = getmaxy() / 2;
/* loop through the available colors */
for (bkcol=0; bkcol<=maxcolor; bkcol++)
{
/* clear the screen */
cleardevice();
/* select a new background color */
setbkcolor(bkcol);
/* output a messsage */
if (bkcol == WHITE)
setcolor(EGA_BLUE);
sprintf(msg, "Background color: %d", bkcol);
outtextxy(x, y, msg);
getch();
}
/* clean up */
closegraph();
return 0;
}
函数名: setblock
功 能: 修改先前已分配的DOS存储段大小
用 法: int setblock(int seg, int newsize);
程序例:
#include
#include
#include
#include
int main(void)
{
unsigned int size, segp;
int stat;
size = 64; /* (64 x 16) = 1024 bytes */
stat = allocmem(size, &segp);
if (stat == -1)
printf("Allocated memory at segment: %X\n", segp);
else
{
printf("Failed: maximum number of paragraphs available is %d\n",
stat);
exit(1);
}
stat = setblock(segp, size * 2);
if (stat == -1)
printf("Expanded memory block at segment: %X\n", segp);
else
printf("Failed: maximum number of paragraphs available is %d\n",
stat);
freemem(segp);
return 0;
}
函数名: setbuf
功 能: 把缓冲区与流相联
用 法: void setbuf(FILE *steam, char *buf);
程序例:
#include
/* BUFSIZ is defined in stdio.h */
char outbuf[BUFSIZ];
int main(void)
{
/* attach a buffer to the standard output stream */
setbuf(stdout, outbuf);
/* put some characters into the buffer */
puts("This is a test of buffered output.\n\n");
puts("This output will go into outbuf\n");
puts("and won';t appear until the buffer\n");
puts("fills up or we flush the stream.\n");
/* flush the output buffer */
fflush(stdout);
return 0;
}
函数名: setcbrk
功 能: 设置Control-break
用 法: int setcbrk(int value);
程序例:
#include
#include
#include
int main(void)
{
int break_flag;
printf("Enter 0 to turn control break off\n");
printf("Enter 1 to turn control break on\n");
break_flag = getch() - 0;
setcbrk(break_flag);
if (getcbrk())
printf("Cntrl-brk flag is on\n");
else
printf("Cntrl-brk flag is off\n");
return 0;
}
函数名: setcolor
功 能: 设置当前画线颜色
用 法: void far setcolor(int color);
程序例:
#include
#include
#include
#include
int main(void)
{
/* select a driver and mode that supports */
/* multiple drawing colors. */
int gdriver = EGA, gmode = EGAHI, errorcode;
int color, maxcolor, x, y;
char msg[80];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
/* maximum color index supported */
maxcolor = getmaxcolor();
/* for centering text messages */
settextjustify(CENTER_TEXT, CENTER_TEXT);
x = getmaxx() / 2;
y = getmaxy() / 2;
/* loop through the available colors */
for (color=1; color<=maxcolor; color++)
{
/* clear the screen */
cleardevice();
/* select a new background color */
setcolor(color);
/* output a messsage */
sprintf(msg, "Color: %d", color);
outtextxy(x, y, msg);
getch();
}
/* clean up */
closegraph();
return 0;
}
函数名: setdate
功 能: 设置DOS日期
用 法: void setdate(struct date *dateblk);
程序例:
#include
#include
#include
int main(void)
{
struct date reset;
struct date save_date;
getdate(&save_date);
printf("Original date:\n");
system("date");
reset.da_year = 2001;
reset.da_day = 1;
reset.da_mon = 1;
setdate(&reset);
printf("Date after setting:\n");
system("date");
setdate(&save_date);
printf("Back to original date:\n");
system("date");
return 0;
}
函数名: setdisk
功 能: 设置当前磁盘驱动器
用 法: int setdisk(int drive);
程序例:
#include
#include
int main(void)
{
int save, disk, disks;
/* save original drive */
save = getdisk();
/* print number of logic drives */
disks = setdisk(save);
printf("%d logical drives on the system\n\n", disks);
/* print the drive letters available */
printf("Available drives:\n");
for (disk = 0;disk < 26;++disk)
{
setdisk(disk);
if (disk == getdisk())
printf("%c: drive is available\n", disk + ';a';);
}
setdisk(save);
return 0;
}
函数名: setdta
功 能: 设置磁盘传输区地址
用 法: void setdta(char far *dta);
程序例:
#include
#include
#include
#include
int main(void)
{
char line[80], far *save_dta;
char buffer[256] = "SETDTA test!";
struct fcb blk;
int result;
/* get new file name from user */
printf("Enter a file name to create:");
gets(line);
/* parse the new file name to the dta */
parsfnm(line, &blk, 1);
printf("%d %s\n", blk.fcb_drive, blk.fcb_name);
/* request DOS services to create file */
if (bdosptr(0x16, &blk, 0) == -1)
{
perror("Error creating file");
exit(1);
}
/* save old dta and set new dta */
save_dta = getdta();
setdta(buffer);
/* write new records */
blk.fcb_recsize = 256;
blk.fcb_random = 0L;
result = randbwr(&blk, 1);
printf("result = %d\n", result);
if (!result)
printf("Write OK\n");
else
{
perror("Disk error");
exit(1);
}
/* request DOS services to close the file */
if (bdosptr(0x10, &blk, 0) == -1)
{
perror("Error closing file");
exit(1);
}
/* reset the old dta */
setdta(save_dta);
return 0;
}
函数名: setfillpattern
功 能: 选择用户定义的填充模式
用 法: void far setfillpattern(char far *upattern, int color);
程序例:
#include
#include
#include
#include
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int maxx, maxy;
/* a user defined fill pattern */
char pattern[8] = {0x00, 0x70, 0x20, 0x27, 0x24, 0x24, 0x07, 0x00};
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
maxx = getmaxx();
maxy = getmaxy();
setcolor(getmaxcolor());
/* select a user defined fill pattern */
setfillpattern(pattern, getmaxcolor());
/* fill the screen with the pattern */
bar(0, 0, maxx, maxy);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setfillstyle
功 能: 设置填充模式和颜色
用 法: void far setfillstyle(int pattern, int color);
程序例:
#include
#include
#include
#include
#include
/* the names of the fill styles supported */
char *fname[] = { "EMPTY_FILL",
"SOLID_FILL",
"LINE_FILL",
"LTSLASH_FILL",
"SLASH_FILL",
"BKSLASH_FILL",
"LTBKSLASH_FILL",
"HATCH_FILL",
"XHATCH_FILL",
"INTERLEAVE_FILL",
"WIDE_DOT_FILL",
"CLOSE_DOT_FILL",
"USER_FILL"
};
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy;
char stylestr[40];
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
for (style = EMPTY_FILL; style < USER_FILL; style++)
{
/* select the fill style */
setfillstyle(style, getmaxcolor());
/* convert style into a string */
strcpy(stylestr, fname[style]);
/* fill a bar */
bar3d(0, 0, midx-10, midy, 0, 0);
/* output a message */
outtextxy(midx, midy, stylestr);
/* wait for a key */
getch();
cleardevice();
}
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setftime
功 能: 设置文件日期和时间
用 法: int setftime(int handle, struct ftime *ftimep);
程序例:
#include
#include
#include
#include
int main(void)
{
struct ftime filet;
FILE *fp;
if ((fp = fopen("TEST.$$$", "w")) == NULL)
{
perror("Error:");
exit(1);
}
fprintf(fp, "testing...\n");
/* load ftime structure with new time and date */
filet.ft_tsec = 1;
filet.ft_min = 1;
filet.ft_hour = 1;
filet.ft_day = 1;
filet.ft_month = 1;
filet.ft_year = 21;
/* show current directory for time and date */
system("dir TEST.$$$");
/* change the time and date stamp*/
setftime(fileno(fp), &filet);
/* close and remove the temporary file */
fclose(fp);
system("dir TEST.$$$");
unlink("TEST.$$$");
return 0;
}
函数名: setgraphbufsize
功 能: 改变内部图形缓冲区的大小
用 法: unsigned far setgraphbufsize(unsigned bufsize);
程序例:
#include
#include
#include
#include
#define BUFSIZE 1000 /* internal graphics buffer size */
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int x, y, oldsize;
char msg[80];
/* set the size of the internal graphics buffer */
/* before making a call to initgraph. */
oldsize = setgraphbufsize(BUFSIZE);
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
x = getmaxx() / 2;
y = getmaxy() / 2;
/* output some messages */
sprintf(msg, "Graphics buffer size: %d", BUFSIZE);
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, msg);
sprintf(msg, "Old graphics buffer size: %d", oldsize);
outtextxy(x, y+textheight("W"), msg);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setgraphmode
功 能: 将系统设置成图形模式且清屏
用 法: void far setgraphmode(int mode);
程序例:
#include
#include
#include
#include
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int x, y;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
x = getmaxx() / 2;
y = getmaxy() / 2;
/* output a message */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "Press any key to exit graphics:");
getch();
/* restore system to text mode */
restorecrtmode();
printf("We';re now in text mode.\n");
printf("Press any key to return to graphics mode:");
getch();
/* return to graphics mode */
setgraphmode(getgraphmode());
/* output a message */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "We';re back in graphics mode.");
outtextxy(x, y+textheight("W"), "Press any key to halt:");
/* clean up */
getch();
closegraph();
return 0;
}
函数名: sound
功 能: 以指定频率打开PC扬声器
用 法: void sound(unsigned frequency);
程序例:
/* Emits a 7-Hz tone for 10 seconds.
Your PC may not be able to emit a 7-Hz tone. */
#include
int main(void)
{
sound(7);
delay(10000);
nosound();
return 0;
}
函数名: spawnl
功 能: 创建并运行子程序
用 法: int spawnl(int mode, char *pathname, char *arg0,
arg1, ... argn, NULL);
程序例:
#include
#include
#include
int main(void)
{
int result;
clrscr();
result = spawnl(P_WAIT, "tcc.exe", NULL);
if (result == -1)
{
perror("Error from spawnl");
exit(1);
}
return 0;
}
函数名: spawnle
功 能: 创建并运行子程序
用 法: int spawnle(int mode, char *pathname, char *arg0,
arg1,..., argn, NULL);
程序例:
/* spawnle() example */
#include
#include
#include
int main(void)
{
int result;
clrscr();
result = spawnle(P_WAIT, "tcc.exe", NULL, NULL);
if (result == -1)
{
perror("Error from spawnle");
exit(1);
}
return 0;
}
函数名: sprintf
功 能: 送格式化输出到字符串中
用 法: int sprintf(char *string, char *farmat [,argument,...]);
程序例:
#include
#include
int main(void)
{
char buffer[80];
sprintf(buffer, "An approximation of Pi is %f\n", M_PI);
puts(buffer);
return 0;
}
函数名: sqrt
功 能: 计算平方根
用 法: double sqrt(double x);
程序例:
#include
#include
int main(void)
{
double x = 4.0, result;
result = sqrt(x);
printf("The square root of %lf is %lf\n", x, result);
return 0;
}
函数名: srand
功 能: 初始化随机数发生器
用 法: void srand(unsigned seed);
程序例:
#include
#include
#include
int main(void)
{
int i;
time_t t;
srand((unsigned) time(&t));
printf("Ten random numbers from 0 to 99\n\n");
for(i=0; i<10; i++)
printf("%d\n", rand() % 100);
return 0;
}
函数名: sscanf
功 能: 执行从字符串中的格式化输入
用 法: int sscanf(char *string, char *format[,argument,...]);
程序例:
#include
#include
int main(void)
{
char label[20];
char name[20];
int entries = 0;
int loop, age;
double salary;
struct Entry_struct
{
char name[20];
int age;
float salary;
} entry[20];
/* Input a label as a string of characters restricting to 20 characters */
printf("\n\nPlease enter a label for the chart: ");
scanf("%20s", label);
fflush(stdin); /* flush the input stream in case of bad input */
/* Input number of entries as an integer */
printf("How many entries will there be? (less than 20) ");
scanf("%d", &entries);
fflush(stdin); /* flush the input stream in case of bad input */
/* input a name restricting input to only letters upper or lower case */
for (loop=0;loop
#include
#include
#define FILENAME "TEST.$$$"
int main(void)
{
struct stat statbuf;
FILE *stream;
/* open a file for update */
if ((stream = fopen(FILENAME, "w+")) == NULL)
{
fprintf(stderr, "Cannot open output file.\n");
return(1);
}
/* get information about the file */
stat(FILENAME, &statbuf);
fclose(stream);
/* display the information returned */
if (statbuf.st_mode & S_IFCHR)
printf("Handle refers to a device.\n");
if (statbuf.st_mode & S_IFREG)
printf("Handle refers to an ordinary file.\n");
if (statbuf.st_mode & S_IREAD)
printf("User has read permission on file.\n");
if (statbuf.st_mode & S_IWRITE)
printf("User has write permission on file.\n");
printf("Drive letter of file: %c\n", ';A';+statbuf.st_dev);
printf("Size of file in bytes: %ld\n", statbuf.st_size);
printf("Time file last opened: %s\n", ctime(&statbuf.st_ctime));
return 0;
}
函数名: _status87
功 能: 取浮点状态
用 法: unsigned int _status87(void);
程序例:
#include
#include
int main(void)
{
float x;
double y = 1.5e-100;
printf("Status 87 before error: %x\n", _status87());
x = y; /* <-- force an error to occur */
y = x;
printf("Status 87 after error : %x\n", _status87());
return 0;
}
函数名: stime
功 能: 设置时间
用 法: int stime(long *tp);
程序例:
#include
#include
#include
int main(void)
{
time_t t;
struct tm *area;
t = time(NULL);
area = localtime(&t);
printf("Number of seconds since 1/1/1970 is: %ld\n", t);
printf("Local time is: %s", asctime(area));
t++;
area = localtime(&t);
printf("Add a second: %s", asctime(area));
t += 60;
area = localtime(&t);
printf("Add a minute: %s", asctime(area));
t += 3600;
area = localtime(&t);
printf("Add an hour: %s", asctime(area));
t += 86400L;
area = localtime(&t);
printf("Add a day: %s", asctime(area));
t += 2592000L;
area = localtime(&t);
printf("Add a month: %s", asctime(area));
t += 31536000L;
area = localtime(&t);
printf("Add a year: %s", asctime(area));
return 0;
}
函数名: stpcpy
功 能: 拷贝一个字符串到另一个
用 法: char *stpcpy(char *destin, char *source);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
stpcpy(string, str1);
printf("%s\n", string);
return 0;
}
函数名: strcat
功 能: 字符串拼接函数
用 法: char *strcat(char *destin, char *source);
程序例:
#include
#include
int main(void)
{
char destination[25];
char *blank = " ", *c = "C++", *Borland = "Borland";
strcpy(destination, Borland);
strcat(destination, blank);
strcat(destination, c);
printf("%s\n", destination);
return 0;
}
函数名: strchr
功 能: 在一个串中查找给定字符的第一个匹配之处\
用 法: char *strchr(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[15];
char *ptr, c = ';r';;
strcpy(string, "This is a string");
ptr = strchr(string, c);
if (ptr)
printf("The character %c is at position: %d\n", c, ptr-string);
else
printf("The character was not found\n");
return 0;
}
函数名: strcmp
功 能: 串比较
用 法: int strcmp(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";
int ptr;
ptr = strcmp(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
else
printf("buffer 2 is less than buffer 1\n");
ptr = strcmp(buf2, buf3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 3\n");
else
printf("buffer 2 is less than buffer 3\n");
return 0;
}
函数名: strncmpi
功 能: 将一个串中的一部分与另一个串比较, 不管大小写
用 法: int strncmpi(char *str1, char *str2, unsigned maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = strcmpi(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名: strcpy
功 能: 串拷贝
用 法: char *strcpy(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
strcpy(string, str1);
printf("%s\n", string);
return 0;
}
函数名: strcspn
功 能: 在串中查找第一个给定字符集内容的段
用 法: int strcspn(char *str1, char *str2);
程序例:
#include
#include
#include
int main(void)
{
char *string1 = "1234567890";
char *string2 = "747DC8";
int length;
length = strcspn(string1, string2);
printf("Character where strings intersect is at position %d\n", length);
return 0;
}
函数名: strdup
功 能: 将串拷贝到新建的位置处
用 法: char *strdup(char *str);
程序例:
#include
#include
#include
int main(void)
{
char *dup_str, *string = "abcde";
dup_str = strdup(string);
printf("%s\n", dup_str);
free(dup_str);
return 0;
}
函数名: stricmp
功 能: 以大小写不敏感方式比较两个串
用 法: int stricmp(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = stricmp(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名: strerror
功 能: 返回指向错误信息字符串的指针
用 法: char *strerror(int errnum);
程序例:
#include
#include
int main(void)
{
char *buffer;
buffer = strerror(errno);
printf("Error: %s\n", buffer);
return 0;
}
函数名: strcmpi
功 能: 将一个串与另一个比较, 不管大小写
用 法: int strcmpi(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = strcmpi(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名: strncmp
功 能: 串比较
用 法: int strncmp(char *str1, char *str2, int maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";
int ptr;
ptr = strncmp(buf2,buf1,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
else
printf("buffer 2 is less than buffer 1\n");
ptr = strncmp(buf2,buf3,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 3\n");
else
printf("buffer 2 is less than buffer 3\n");
return(0);
}
函数名: strncmpi
功 能: 把串中的一部分与另一串中的一部分比较, 不管大小写
用 法: int strncmpi(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBBccc", *buf2 = "bbbccc";
int ptr;
ptr = strncmpi(buf2,buf1,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名: strncpy
功 能: 串拷贝
用 法: char *strncpy(char *destin, char *source, int maxlen);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
strncpy(string, str1, 3);
string[3] = ';\0';;
printf("%s\n", string);
return 0;
}
函数名: strnicmp
功 能: 不注重大小写地比较两个串
用 法: int strnicmp(char *str1, char *str2, unsigned maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBBccc", *buf2 = "bbbccc";
int ptr;
ptr = strnicmp(buf2, buf1, 3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名: strnset
功 能: 将一个串中的所有字符都设为指定字符
用 法: char *strnset(char *str, char ch, unsigned n);
程序例:
#include
#include
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz";
char letter = ';x';;
printf("string before strnset: %s\n", string);
strnset(string, letter, 13);
printf("string after strnset: %s\n", string);
return 0;
}
函数名: strpbrk
功 能: 在串中查找给定字符集中的字符
用 法: char *strpbrk(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *string1 = "abcdefghijklmnopqrstuvwxyz";
char *string2 = "onm";
char *ptr;
ptr = strpbrk(string1, string2);
if (ptr)
printf("strpbrk found first character: %c\n", *ptr);
else
printf("strpbrk didn';t find character in set\n");
return 0;
}
函数名: strrchr
功 能: 在串中查找指定字符的最后一个出现
用 法: char *strrchr(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[15];
char *ptr, c = ';r';;
strcpy(string, "This is a string");
ptr = strrchr(string, c);
if (ptr)
printf("The character %c is at position: %d\n", c, ptr-string);
else
printf("The character was not found\n");
return 0;
}
函数名: strrev
功 能: 串倒转
用 法: char *strrev(char *str);
程序例:
#include
#include
int main(void)
{
char *forward = "string";
printf("Before strrev(): %s\n", forward);
strrev(forward);
printf("After strrev(): %s\n", forward);
return 0;
}
函数名: strset
功 能: 将一个串中的所有字符都设为指定字符
用 法: char *strset(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[10] = "123456789";
char symbol = ';c';;
printf("Before strset(): %s\n", string);
strset(string, symbol);
printf("After strset(): %s\n", string);
return 0;
}
函数名: strspn
功 能: 在串中查找指定字符集的子集的第一次出现
用 法: int strspn(char *str1, char *str2);
程序例:
#include
#include
#include
int main(void)
{
char *string1 = "1234567890";
char *string2 = "123DC8";
int length;
length = strspn(string1, string2);
printf("Character where strings differ is at position %d\n", length);
return 0;
}
函数名: strstr
功 能: 在串中查找指定字符串的第一次出现
用 法: char *strstr(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *str1 = "Borland International", *str2 = "nation", *ptr;
ptr = strstr(str1, str2);
printf("The substring is: %s\n", ptr);
return 0;
}
函数名: strtod
功 能: 将字符串转换为double型值
用 法: double strtod(char *str, char **endptr);
程序例:
#include
#include
int main(void)
{
char input[80], *endptr;
double value;
printf("Enter a floating point number:");
gets(input);
value = strtod(input, &endptr);
printf("The string is %s the number is %lf\n", input, value);
return 0;
}
函数名: strtok
功 能: 查找由在第二个串中指定的分界符分隔开的单词
用 法: char *strtok(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char input[16] = "abc,d";
char *p;
/* strtok places a NULL terminator
in front of the token, if found */
p = strtok(input, ",");
if (p) printf("%s\n", p);
/* A second call to strtok using a NULL
as the first parameter returns a pointer
to the character following the token */
p = strtok(NULL, ",");
if (p) printf("%s\n", p);
return 0;
}
函数名: strtol
功 能: 将串转换为长整数
用 法: long strtol(char *str, char **endptr, int base);
程序例:
#include
#include
int main(void)
{
char *string = "87654321", *endptr;
long lnumber;
/* strtol converts string to long integer */
lnumber = strtol(string, &endptr, 10);
printf("string = %s long = %ld\n", string, lnumber);
return 0;
}
函数名: strupr
功 能: 将串中的小写字母转换为大写字母
用 法: char *strupr(char *str);
程序例:
#include
#include
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;
/* converts string to upper case characters */
ptr = strupr(string);
printf("%s\n", ptr);
return 0;
}
函数名: swab
功 能: 交换字节
用 法: void swab (char *from, char *to, int nbytes);
程序例:
#include
#include
#include
char source[15] = "rFna koBlrna d";
char target[15];
int main(void)
{
swab(source, target, strlen(source));
printf("This is target: %s\n", target);
return 0;
}
函数名: system
功 能: 发出一个DOS命令
用 法: int system(char *command);
程序例:
#include
#include
int main(void)
{
printf("About to spawn command.com and run a DOS command\n");
system("dir");
return 0;
}
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