函数名: fscanf 
 功  能: 从一个流中执行格式化输入 
 用  法: #include <stdio.h>
         int fscanf(FILE *stream, char *format[,argument...]); 
 程序例: 
#include <stdlib.h> 
 #include <stdio.h> 
int main(void) 
 { 
    int i; 
printf("Input an integer: ");
   /* read an integer from the 
       standard input stream */ 
    if (fscanf(stdin, "%d", &i)) 
       printf("The integer read was: %i\n", 
              i); 
    else 
    { 
       fprintf(stderr, "Error reading an \ 
               integer from stdin.\n"); 
       exit(1); 
    } 
    return 0; 
 }