函数名: putw 
 功  能: 把一字符或字送到流中 
 用  法: #include <stdio.h> 
         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; 
 }