#include <iostream>
#include <cstdio>

 

using namespace std;

 

int main(int argc, char** argv) {
        FILE* fp = NULL;
        fp = fopen("data.txt", "w");

        fputs("gooooooooogle", fp);
        fclose(fp);
        fp = NULL;

        fp = fopen("data.txt", "r+");

        // 讀取修改前的內容
        char str[50];
        cout << "------------修改前的內容---------" << endl;
        cout << fgets(str, 50, fp) << endl;

 

        // 隨機修改文件.
        rewind(fp);
        fseek(fp, 3L, SEEK_SET);
        //cout << ftell(fp) << endl;
        fputc('A', fp);
        fputc('B', fp);
        fseek(fp, 1L, SEEK_CUR);
        fputc('C', fp);

        // 讀出修改后的內容
        rewind(fp);
        cout << "------------修改后的內容---------" << endl;
        cout << fgets(str, 50, fp) << endl;

        fclose(fp);
        return 0;
}