C++ 同时从2个文件读取数据

　　 //FILE *stdin1;
    //FILE *stdin2;
    //freopen("D:/p/BB/11.txt", "r", stdin);
    //freopen("D:/p/BB/22.txt", "r", stdin2);
    freopen("D:/p/BB/1_2.txt", "w", stdout);
    FILE * fp1 = fopen("D:/p/BB/1.txt", "r");
    FILE * fp2 = fopen("D:/p/BB/2.txt", "r");
    
    double x, y;
    fscanf(fp1,"%lf",&x);//从输入文件读取一个整数
    fscanf(fp2, "%lf", &y);
    //printf("%lf  %lf \n", x, y);