Question

简单acm题，为什么会wrong answer？

题目：
Description
Your task is to Calculate a + b.
Input
There are multiple test cases. Each test case contains only one line. Each line consists of a pair of real number a and b（0<=a,b<=1000000）, separated by a space.
Output

For each case, output the answer in one line rounded to 4 digits after the decimal point.

代码：
#include<stdio.h>
int main()
{
float a,b;
while(scanf("%f %f",&a,&b) != EOF)
{
printf("%.4f\n",(a + b));
}
return 0;
}

Answer 1

改用double吧，float很难保证在1000000以内还有4位小数的精度

Answer 2

%.4f 是输出保留4位小数 亲

追问

难道还要四舍五入！