主函数.txt

一些用到的函数 功能齐全

用  法: double pow(double x, double y); 
程序例: 

#include <math.h> 
#include <stdio.h> 

int main(void) 
{ 
   double x = 2.0, y = 3.0; 

   printf("%lf raised to %lf is %lf\n", x, y, pow(x, y)); 
   return 0; 
} 
  

函数名: pow10 
功  能: 指数函数(10的p次方) 
用  法: double pow10(int p); 
程序例: 

#include <math.h> 
#include <stdio.h> 

int main(void) 
{ 
   double p = 3.0; 

   printf("Ten raised to %lf is %lf\n", p, pow10(p)); 
   return 0; 
} 
  
  

函数名: printf 
功  能: 产生格式化输出的函数 
用  法: int printf(char *format...); 
程序例: 

#include <stdio.h> 
#include <string.h> 

#define I 555 
#define R 5.5 

int main(void) 
{ 
   int i,j,k,l; 
   char buf[7]; 
   char *prefix = buf; 
   char tp[20]; 
   printf("prefix  6d      6o      8x        10.2e        " 
          "10.2f\n"); 
   strcpy(prefix,"%"); 
   for (i = 0; i < 2; i++) 
   { 
      for (j = 0; j < 2; j++) 
         for (k = 0; k < 2; k++) 
     for (l = 0; l < 2; l++) 
            { 
               if (i==0)  strcat(prefix,"-"); 
               if (j==0)  strcat(prefix,"+"); 
               if (k==0)  strcat(prefix,"#"); 
               if (l==0)  strcat(prefix,"0"); 
               printf("%5s |",prefix); 
               strcpy(tp,prefix); 
               strcat(tp,"6d |"); 
               printf(tp,I); 
               strcpy(tp,""); 
               strcpy(tp,prefix); 
               strcat(tp,"6o |"); 
               printf(tp,I); 
               strcpy(tp,""); 
               strcpy(tp,prefix); 
               strcat(tp,"8x |"); 
               printf(tp,I); 
               strcpy(tp,""); 
               strcpy(tp,prefix); 
        strcat(tp,"10.2e |"); 
        printf(tp,R); 
        strcpy(tp,prefix); 
        strcat(tp,"10.2f |"); 
        printf(tp,R); 
        printf("  \n"); 
        strcpy(prefix,"%"); 
     } 
       } 
   return 0; 
} 
  
  

函数名: putc 
功  能: 输出一字符到指定流中 
用  法: int putc(int ch, FILE *stream); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
   char msg[] = "Hello world\n"; 
   int i = 0; 

   while (msg[i]) 
      putc(msg[i++], stdout); 
   return 0; 
} 
  
  

函数名: putch 
功  能: 输出字符到控制台 
用  法: int putch(int ch); 
程序例: 

#include <stdio.h> 
#include <conio.h> 

int main(void) 
{ 
   char ch = 0; 

   printf("Input a string:"); 
   while ((ch != '\r')) 
   { 
      ch = getch(); 
      putch(ch); 
   } 
   return 0; 
} 
  
  

函数名: putchar 
功  能: 在stdout上输出字符 
用  法: int putchar(int ch); 
程序例: 

#include <stdio.h> 

/* define some box-drawing characters */ 
#define LEFT_TOP  0xDA 
#define RIGHT_TOP 0xBF 
#define HORIZ     0xC4 
#define VERT      0xB3 
#define LEFT_BOT  0xC0 
#define RIGHT_BOT 0xD9 

int main(void) 
{ 
   char i, j; 

   /* draw the top of the box */ 
   putchar(LEFT_TOP); 
   for (i=0; i<10; i++) 
      putchar(HORIZ); 
   putchar(RIGHT_TOP); 
   putchar('\n'); 

   /* draw the middle */ 
   for (i=0; i<4; i++) 
   { 
      putchar(VERT); 
      for (j=0; j<10; j++) 
         putchar(' '); 
      putchar(VERT); 
      putchar('\n'); 
   } 

   /* draw the bottom */ 
   putchar(LEFT_BOT); 
   for (i=0; i<10; i++) 
      putchar(HORIZ); 
   putchar(RIGHT_BOT); 
   putchar('\n'); 

   return 0; 
} 
  
  

函数名: putenv 
功  能: 把字符串加到当前环境中 
用  法: int putenv(char *envvar); 
程序例: 

#include <stdio.h> 
#include <stdlib.h> 
#include <alloc.h> 
#include <string.h> 
#include <dos.h> 

int main(void) 
{ 
   char *path, *ptr; 
   int i = 0; 

   /* get the current path environment */ 
   ptr = getenv("PATH"); 

   /* set up new path */ 
   path = malloc(strlen(ptr)+15); 
   strcpy(path,"PATH="); 
   strcat(path,ptr); 
   strcat(path,";c:\\temp"); 

   /* replace the current path and display current environment */ 
   putenv(path); 
   while (environ[i]) 
       printf("%s\n",environ[i++]); 

   return 0; 
} 
  
  

函数名: putimage 
功  能: 在屏幕上输出一个位图 
用  法: void far putimage(int x, int y, void far *bitmap, int op); 
程序例: 

#include <graphics.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <conio.h> 

#define ARROW_SIZE 10 

void draw_arrow(int x, int y); 

int main(void) 
{ 
   /* request autodetection */ 
   int gdriver = DETECT, gmode, errorcode; 
   void *arrow; 
   int x, y, maxx; 
   unsigned int size; 

   /* 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(); 
   x = 0; 
   y = getmaxy() / 2; 

   /* draw the image to be grabbed */ 
   draw_arrow(x, y); 

   /* calculate the size of the image */ 
   size = imagesize(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE); 

   /* allocate memory to hold the image */ 
   arrow = malloc(size); 

   /* grab the image */ 
   getimage(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE, arrow); 

   /* repeat until a key is pressed */ 
   while (!kbhit()) 
   { 
      /* erase old image */ 
      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT); 

      x += ARROW_SIZE; 
      if (x >= maxx) 
          x = 0; 

      /* plot new image */ 
      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT); 
   } 

   /* clean up */ 
   free(arrow); 
   closegraph(); 
   return 0; 
} 

void draw_arrow(int x, int y) 
{ 
   /* draw an arrow on the screen */ 
   moveto(x, y); 
   linerel(4*ARROW_SIZE, 0); 
   linerel(-2*ARROW_SIZE, -1*ARROW_SIZE); 
   linerel(0, 2*ARROW_SIZE); 
   linerel(2*ARROW_SIZE, -1*ARROW_SIZE); 
} 
  
  

函数名: putpixel 
功  能: 在指定位置画一像素 
用  法: void far putpixel (int x, int y, int pixelcolor); 
程序例: 

#include <graphics.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <conio.h> 
#include <dos.h> 

#define PIXEL_COUNT 1000 
#define DELAY_TIME  100  /* in milliseconds */ 

int main(void) 
{ 
   /* request autodetection */ 
   int gdriver = DETECT, gmode, errorcode; 
   int i, x, y, color, maxx, maxy, maxcolor, seed; 

   /* 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() + 1; 
   maxy = getmaxy() + 1; 
   maxcolor = getmaxcolor() + 1; 

   while (!kbhit()) 
   { 
      /* seed the random number generator */ 
      seed = random(32767); 
      srand(seed); 
      for (i=0; i<PIXEL_COUNT; i++) 
      { 
  x = random(maxx); 
         y = random(maxy); 
         color = random(maxcolor); 
         putpixel(x, y, color); 
      } 

      delay(DELAY_TIME); 
      srand(seed); 
      for (i=0; i<PIXEL_COUNT; i++) 
      { 
  x = random(maxx); 
  y = random(maxy); 
  color = random(maxcolor); 
  if (color == getpixel(x, y)) 
     putpixel(x, y, 0); 
      } 
   } 

   /* clean up */ 
   getch(); 
   closegraph(); 
   return 0; 
} 
  
  

函数名: puts 
功  能: 送一字符串到流中 
用  法: int puts(char *string); 
程序例: 

#include <stdio.h> 
int main(void) 
{ 
   char string[] = "This is an example output string\n"; 

   puts(string); 
   return 0; 
} 
  
  

函数名: puttext 
功  能: 将文本从存储区拷贝到屏幕 
用  法: int puttext(int left, int top, int right, int bottom, void *source); 
程序例: 

#include <conio.h> 
int main(void) 
{ 
   char buffer[512]; 

   /* put some text to the console */ 
   clrscr(); 
   gotoxy(20, 12); 
   cprintf("This is a test.  Press any key to continue ..."); 
   getch(); 

   /* grab screen contents */ 
   gettext(20, 12, 36, 21,buffer); 
   clrscr(); 

   /* put selected characters back to the screen */ 
   gotoxy(20, 12); 
   puttext(20, 12, 36, 21, buffer); 
   getch(); 

   return 0; 
} 
  
  

函数名: putw 
功  能: 把一字符或字送到流中 
用  法: int putw(int w, FILE *stream); 
程序例: 

#include <stdio.h> 
#include <stdlib.h> 

#define FNAME "test.$$$" 

int main(void) 
{ 
   FILE *fp; 
   int word; 

   /* place the word in a file */ 
   fp = fopen(FNAME, "wb"); 
   if (fp == NULL) 
   { 
      printf("Error opening file %s\n", FNAME); 
      exit(1); 
   } 

   word = 94; 
   putw(word,fp); 
   if (ferror(fp)) 
       printf("Error writing to file\n"); 
   else 
       printf("Successful write\n"); 
   fclose(fp); 

   /* reopen the file */ 
   fp = fopen(FNAME, "rb"); 
   if (fp == NULL) 
   { 
      printf("Error opening file %s\n", FNAME); 
      exit(1); 
   } 

   /* extract the word */ 
   word = getw(fp); 
   if (ferror(fp)) 
       printf("Error reading file\n"); 
   else 
       printf("Successful read: word = %d\n", word); 

   /* clean up */ 
   fclose(fp); 
   unlink(FNAME); 

   return 0; 
} 
  

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Copyright by 潇 逸 1999 
建议用 IE4.0 800*600真彩色浏览本站以达到最好效果
网站制作：潇 逸(周 炜) 
  
函数名: qsort 
功  能: 使用快速排序例程进行排序 
用  法: void qsort(void *base, int nelem, int width, int (*fcmp)()); 
程序例: 

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 

int sort_function( const void *a, const void *b); 

char list[5][4] = { "cat", "car", "cab", "cap", "can" }; 
  

int main(void) 
{ 
   int  x; 

   qsort((void *)list, 5, sizeof(list[0]), sort_function); 
   for (x = 0; x < 5; x++) 
      printf("%s\n", list[x]); 
   return 0; 
} 

int sort_function( const void *a, const void *b) 
{ 
   return( strcmp(a,b) ); 
} 
  

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版权所有(C) 潇逸天地
Copyright by 潇 逸 1999 
建议用 IE4.0 800*600真彩色浏览本站以达到最好效果
网站制作：潇 逸(周 炜)