这是我写的: #include <stdio.h> int main(void) { int a,b,c; double average; scanf("%d%d%d",&a,&b,&c); average=(a+b+c)/3; printf("average = %.2f\n", average); return 0; } 虽然定义了average为double,但输出来怎么还是整数,比如: 输入2 3 9,出来是4.00