C语言实例56：fputc()和fgetc()

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

int main(int argc, char *argv[])
{
    FILE *fp;
    char str[100];
    int i;
    if((fp = fopen("file.txt","w")) == NULL)
    {
        printf("无法打开文件\n");
        exit(0);
    }
    printf("请输入一个字符串： \n");
    gets(str);

    for(i = 0; str[i] != '.';i++)
    {
        if(str[i] >= 'a' && str[i] <= 'z')
            str[i] = str[i] -32;
        fputc(str[i], fp);
    }

    fclose(fp);
    fp = fopen("file.txt","r");
    for(i = 0; str[i] != '.';i++)
        str[i] = fgetc(fp);
    printf("%s\n",str);
    fclose(fp);

    system("pause");
    return 0;
}