函數名: parsfnm  
功  能: 分析文件名  
用  法: char *parsfnm (char *cmdline, struct fcb *fcbptr, int option);  
程序例:  

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

int main(void)  
{  
   char line[80];  
   struct fcb blk;  

   /* get file name */  
   printf("Enter drive and file name (no path - ie. a:file.dat)\n");  
   gets(line);  

   /* put file name in fcb */  
   if (parsfnm(line, &blk, 1) == NULL)  
      printf("Error in parsfm call\n");  
   else  
      printf("Drive #%d  Name: %11s\n", blk.fcb_drive, blk.fcb_name);  

   return 0;  
}  
   
   

函數名: peek  
功  能: 檢查存儲單元  
用  法: int peek(int segment, unsigned offset);  
程序例:  

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

int main(void)  
{  
   int value = 0;  

   printf("The current status of your keyboard is:\n");  
   value = peek(0x0040, 0x0017);  
   if (value & 1)  
      printf("Right shift on\n");  
   else  
      printf("Right shift off\n");  

   if (value & 2)  
      printf("Left shift on\n");  
   else  
      printf("Left shift off\n");  

   if (value & 4)  
      printf("Control key on\n");  
   else  
      printf("Control key off\n");  

   if (value & 8)  
      printf("Alt key on\n");  
   else  
      printf("Alt key off\n");  

   if (value & 16)  
      printf("Scroll lock on\n");  
   else  
      printf("Scroll lock off\n");  

   if (value & 32)  
      printf("Num lock on\n");  
   else  
      printf("Num lock off\n");  

   if (value & 64)  
      printf("Caps lock on\n");  
   else  
      printf("Caps lock off\n");  

   return 0;  
}  
   
   

函數名: peekb  
功  能: 檢查存儲單元  
用  法: char peekb (int segment, unsigned offset);  
程序例:  

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

int main(void)  
{  
   int value = 0;  

   printf("The current status of your keyboard is:\n");  
   value = peekb(0x0040, 0x0017);  
   if (value & 1)  
      printf("Right shift on\n");  
   else  
      printf("Right shift off\n");  

   if (value & 2)  
      printf("Left shift on\n");  
   else  
      printf("Left shift off\n");  

   if (value & 4)  
      printf("Control key on\n");  
   else  
      printf("Control key off\n");  

   if (value & 8)  
      printf("Alt key on\n");  
   else  
      printf("Alt key off\n");  

   if (value & 16)  
      printf("Scroll lock on\n");  
   else  
      printf("Scroll lock off\n");  

   if (value & 32)  
      printf("Num lock on\n");  
   else  
      printf("Num lock off\n");  

   if (value & 64)  
      printf("Caps lock on\n");  
   else  
      printf("Caps lock off\n");  

   return 0;  
}  
   
   

函數名: perror  
功  能: 系統錯誤信息  
用  法: void perror(char *string);  
程序例:  

#include <stdio.h>  

int main(void)  
{  
   FILE *fp;  

   fp = fopen("perror.dat", "r");  
   if (!fp)  
      perror("Unable to open file for reading");  
   return 0;  
}  
   
   

函數名: pieslice  
功  能: 繪制并填充一個扇形  
用  法: void far pieslice(int x, int stanle, int endangle, int radius);  
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;  
   int stangle = 45, endangle = 135, radius = 100;  

   /* 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;  

   /* set fill style and draw a pie slice */  
   setfillstyle(EMPTY_FILL, getmaxcolor());  
   pieslice(midx, midy, stangle, endangle, radius);  

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

函數名: poke  
功  能: 存值到一個給定存儲單元  
用  法: void poke(int segment, int offset, int value);  
程序例:  

#include <dos.h>  
#include <conio.h>  

int main(void)  
{  
   clrscr();  
   cprintf("Make sure the scroll lock key is off and press any key\r\n");  
   getch();  
   poke(0x0000,0x0417,16);  
   cprintf("The scroll lock is now on\r\n");  
   return 0;  
}  
   
   

函數名: pokeb  
功  能: 存值到一個給定存儲單元  
用  法: void pokeb(int segment, int offset, char value);  
程序例:  

#include <dos.h>  
#include <conio.h>  

int main(void)  
{  
   clrscr();  
   cprintf("Make sure the scroll lock key is off and press any key\r\n");  
   getch();  
   pokeb(0x0000,0x0417,16);  
   cprintf("The scroll lock is now on\r\n");  
   return 0;  
}  
   
   

函數名: poly  
功  能: 根據參數產生一個多項式  
用  法: double poly(double x, int n, double c[]);  
程序例:  

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

/* polynomial:  x**3 - 2x**2 + 5x - 1 */  

int main(void)  
{  
   double array[] = { -1.0, 5.0, -2.0, 1.0 };  
   double result;  

   result = poly(2.0, 3, array);  
   printf("The polynomial: x**3 - 2.0x**2 + 5x - 1 at 2.0 is %lf\n",  
           result);  
   return 0;  
}  
   
   

函數名: pow  
功  能: 指數函數(x的y次方)  
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;  
}  
   

函數名: pow10  
功  能: 指數函數(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;  
}  
   
   

函數名: printf  
功  能: 產生格式化輸出的函數  
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;  
}  
   
   

函數名: putc  
功  能: 輸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)