C程序实现快速从文件输入和输出到文件

#include <iostream>


int main()
{
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    
    float a,b=0;
    for (;scanf("%f",&a)!=EOF;)
        b+=a;
    printf("$%.2f\n", b/12);

    fprintf(stderr, "Over");

    fclose(stdin);
    fclose(stdout);
    return 0;
}