s.txt

C语言函数大全

用  法: char *strpbrk(char *str1, char *str2);  
程序例:  
#include <stdio.h>  
#include <string.h>  
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 <string.h>  
#include <stdio.h>  
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 <string.h>  
#include <stdio.h>  
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 <stdio.h>  
#include <string.h>  
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 <stdio.h>  
#include <string.h>  
#include <alloc.h>  
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 <stdio.h>  
#include <string.h>  
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 <stdio.h>  
#include <stdlib.h>  
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 <string.h>  
#include <stdio.h>  
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 <stdlib.h>  
#include <stdio.h>  
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 <stdio.h>  
#include <string.h>  
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 <stdlib.h>  
#include <stdio.h>  
#include <string.h>  
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 <stdlib.h>  
#include <stdio.h>  
int main(void)  
{  
   printf("About to spawn command.com and run a DOS command\n");  
   system("dir");  
   return 0;  
}  
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 <stdio.h>   
#include <alloc.h>  
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 <stdio.h>  
#include <conio.h>  
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<entries;++loop)  
   {  
      printf("Entry %d\n", loop);  
      printf("  Name   : ");  
      scanf("%[A-Za-z]", entry[loop].name);  
      fflush(stdin);  /* flush the input stream in case of bad input */  
/* input an age as an integer */  
      printf("  Age    : ");  
      scanf("%d", &entry[loop].age);  
      fflush(stdin);  /* flush the input stream in case of bad input */  

/* input a salary as a float */  
      printf("  Salary : ");  
      scanf("%f", &entry[loop].salary);  
      fflush(stdin); /* flush the input stream in case of bad input */  
   }  
/* Input a name, age and salary as a string, integer, and double */  
   printf("\nPlease enter your name, age and salary\n");  
   scanf("%20s %d %lf", name, &age, &salary);  
   
/* Print out the data that was input */  
   printf("\n\nTable %s\n",label);  
   printf("Compiled by %s  age %d  $%15.2lf\n", name, age, salary);  
   printf("-----------------------------------------------------\n");  
   for (loop=0;loop<entries;++loop)  
      printf("%4d | %-20s | %5d | %15.2lf\n",  
         loop + 1,  
  entry[loop].name,  
  entry[loop].age,  
         entry[loop].salary);  
   printf("-----------------------------------------------------\n");  
   return 0;  
}        
函数名: searchpath  
功  能: 搜索DOS路径  
用  法: char *searchpath(char *filename);  
程序例:  
#include <stdio.h>  
#include <dir.h>  
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 <graphics.h>  
#include <stdlib.h>  
#include <stdio.h>  
#include <conio.h>  
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<USER_FILL; i++)  
   {  
      /* set the fill style */  
      setfillstyle(i, getmaxcolor());  
  /* draw the sector slice */  
      sector(midx, midy, stangle, endangle, xrad, yrad);  
     getch();  
   }  
   /* clean up */  
   closegraph();  
   return 0;  
}  
函数名: segread  
功  能: 读段寄存器值  
用  法: void segread(struct SREGS *segtbl);  
程序例:  
#include <stdio.h>  
#include <dos.h>  

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 <graphics.h>  
#include <stdlib.h>  
#include <stdio.h>  
#include <conio.h>  
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 <graphics.h>  
#include <stdlib.h>  
#include <stdio.h>  
#include <conio.h>  
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 <graphics.h>  
#include <stdlib.h>  
#include <stdio.h>  
#include <conio.h>  
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 <graphics.h>  
#include <stdlib.h>  
#include <stdio.h>  
#include <conio.h>  
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();