wdg_022c.txt

c编程宝典,详细介绍有关c的资料

       close(handle); 
   } 
   else 
   { 
       printf("Error opening file\n"); 
   } 
   return 0; 
} 
  
  
  

函数名: clock 
功  能: 确定处理器时间 
用  法: clock_t clock(void); 
程序例: 

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

int main(void) 
{ 
   clock_t start, end; 
   start = clock(); 

   delay(2000); 

   end = clock(); 
   printf("The time was: %f\n", (end - start) / CLK_TCK); 

   return 0; 
} 
  
  
  

函数名: closegraph 
功  能: 关闭图形系统 
用  法: void far closegraph(void); 
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 x, y; 

   /* initialize graphics mode */ 
   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 a key to close the graphics system:"); 

   /* wait for a key */ 
   getch(); 

   /* closes down the graphics system */ 
   closegraph(); 

   printf("We're now back in text mode.\n"); 
   printf("Press any key to halt:"); 
   getch(); 
   return 0; 
} 
  
  
  

函数名: clreol 
功  能: 在文本窗口中清除字符到行末 
用  法: void clreol(void); 
程序例: 

#include <conio.h> 

int main(void) 

{ 
   clrscr(); 
   cprintf("The function CLREOL clears all characters from the\r\n"); 
   cprintf("cursor position to the end of the line within the\r\n"); 
   cprintf("current text window, without moving the cursor.\r\n"); 
   cprintf("Press any key to continue . . ."); 
   gotoxy(14, 4); 
   getch(); 

   clreol(); 
   getch(); 

   return 0; 
} 
  
  
  

函数名: clrscr 
功  能: 清除文本模式窗口 
用  法: void clrscr(void); 
程序例: 

#include <conio.h> 

int main(void) 
{ 
   int i; 

   clrscr(); 
   for (i = 0; i < 20; i++) 
      cprintf("%d\r\n", i); 
   cprintf("\r\nPress any key to clear screen"); 
   getch(); 

   clrscr(); 
   cprintf("The screen has been cleared!"); 
   getch(); 

   return 0; 
} 
  
  
  

函数名: coreleft 
功  能: 返回未使用内存的大小 
用  法: unsigned coreleft(void); 
程序例: 

#include <stdio.h> 
#include <alloc.h> 

int main(void) 
{ 
   printf("The difference between the highest allocated block and\n"); 
   printf("the top of the heap is: %lu bytes\n", (unsigned long) coreleft()); 

   return 0; 
} 
  

函数名: cos 
功  能: 余弦函数 
用  法: double cos(double x); 
程序例: 

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

int main(void) 
{ 
   double result; 
   double x = 0.5; 

   result = cos(x); 
   printf("The cosine of %lf is %lf\n", x, result); 
   return 0; 
} 
  
  
  

函数名: cosh 
功  能: 双曲余弦函数 
用  法: dluble cosh(double x); 
程序例: 

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

int main(void) 
{ 
   double result; 
   double x = 0.5; 

   result = cosh(x); 
   printf("The hyperboic cosine of %lf is %lf\n", x, result); 
   return 0; 
} 
  
  
  

函数名: country 
功  能: 返回与国家有关的信息 
用  法: struct COUNTRY *country(int countrycode, struct country *country); 
程序例: 

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

#define USA 0 

int main(void) 
{ 
   struct COUNTRY country_info; 

   country(USA, &country_info); 
   printf("The currency symbol for the USA is: %s\n", 
           country_info.co_curr); 
   return 0; 
} 
  
  
  

函数名: cprintf 
功  能: 送格式化输出至屏幕 
用  法: int cprintf(const char *format[, argument, ...]); 
程序例: 

#include <conio.h> 

int main(void) 
{ 
   /* clear the screen */ 
   clrscr(); 

   /* create a text window */ 
   window(10, 10, 80, 25); 

   /* output some text in the window */ 
   cprintf("Hello world\r\n"); 

   /* wait for a key */ 
   getch(); 
   return 0; 
} 
  
  
  

函数名: cputs 
功  能: 写字符到屏幕 
用  法: void cputs(const char *string); 
程序例: 

#include <conio.h> 

int main(void) 
{ 
   /* clear the screen */ 
   clrscr(); 

   /* create a text window */ 
   window(10, 10, 80, 25); 

   /* output some text in the window */ 
   cputs("This is within the window\r\n"); 

   /* wait for a key */ 
   getch(); 
   return 0; 
} 
  
  
  

函数名: _creat  creat 
功  能: 创建一个新文件或重写一个已存在的文件 
用  法: int creat (const char *filename, int permiss); 
程序例: 

#include <sys\stat.h> 
#include <string.h> 
#include <fcntl.h> 
#include <io.h> 

int main(void) 
{ 
   int handle; 
   char buf[11] = "0123456789"; 

   /* change the default file mode from text to binary */ 
   _fmode = O_BINARY; 

   /* create a binary file for reading and writing */ 
   handle = creat("DUMMY.FIL", S_IREAD | S_IWRITE); 

   /* write 10 bytes to the file */ 
   write(handle, buf, strlen(buf)); 

   /* close the file */ 
   close(handle); 
   return 0; 
} 
  

函数名: creatnew 
功  能: 创建一个新文件 
用  法: int creatnew(const char *filename, int attrib); 
程序例: 

#include <string.h> 
#include <stdio.h> 
#include <errno.h> 
#include <dos.h> 
#include <io.h> 

int main(void) 
{ 
   int handle; 
   char buf[11] = "0123456789"; 

   /* attempt to create a file that doesn't already exist */ 
   handle = creatnew("DUMMY.FIL", 0); 

   if (handle == -1) 
      printf("DUMMY.FIL already exists.\n"); 
   else 
   { 
      printf("DUMMY.FIL successfully created.\n"); 
      write(handle, buf, strlen(buf)); 
      close(handle); 
   } 
   return 0; 
} 
  
  
  

函数名: creattemp 
功  能: 创建一个新文件或重写一个已存在的文件 
用  法: int creattemp(const char *filename, int attrib); 
程序例: 

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

int main(void) 
{ 
   int handle; 
   char pathname[128]; 

   strcpy(pathname, "\\"); 

   /* create a unique file in the root directory */ 
   handle = creattemp(pathname, 0); 

   printf("%s was the unique file created.\n", pathname); 
   close(handle); 
   return 0; 
} 
  
  
  

函数名: cscanf 
功  能: 从控制台执行格式化输入 
用  法: int cscanf(char *format[,argument, ...]); 
程序例: 

#include <conio.h> 

int main(void) 
{ 
   char string[80]; 

   /* clear the screen */ 
   clrscr(); 

   /* Prompt the user for input */ 
   cprintf("Enter a string with no spaces:"); 

   /* read the input */ 
   cscanf("%s", string); 

   /* display what was read */ 
   cprintf("\r\nThe string entered is: %s", string); 
   return 0; 
} 
  
  
  

函数名: ctime 
功  能: 把日期和时间转换为字符串 
用  法: char *ctime(const time_t *time); 
程序例: 

#include <stdio.h> 
#include <time.h> 

int main(void) 
{ 
   time_t t; 

   time(&t); 
   printf("Today's date and time: %s\n", ctime(&t)); 
   return 0; 
} 
  
  
  

函数名: ctrlbrk 
功  能: 设置Ctrl-Break处理程序 
用  法: void ctrlbrk(*fptr)(void); 
程序例: 

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

#define ABORT 0 

int c_break(void) 
{ 
   printf("Control-Break pressed.  Program aborting ...\n"); 
   return (ABORT); 
} 

int main(void) 
{ 
   ctrlbrk(c_break); 
   for(;;) 
   { 
      printf("Looping... Press <Ctrl-Break> to quit:\n"); 
   } 
   return 0; 
}