C语言非正常结束，计算1+1/2-1/3+1/4-1/5+1/6-…+1/n，保留三位小数，为什么作业检测系统总说非正常结束？

Question

速求帮助！
#include<stdio.h>
void main()
{
float sum = 1.0, x = 2.0, n;
int a = -1;
scanf("%f", &n);
while(x<=n)
{
a = (-1) * a;
sum = sum + a/x; x++;
}
printf("sum=%.3f\n", sum);
return 0;
}

Answer 1

#include<stdio.h>
int main()//可能是这里的void吧,你下面有返回值,其他的我测试了一下都正常的
{
float sum = 1.0, x = 2.0, n;
int a = -1;
scanf("%f", &n);
while(x<=n)
{
a = (-1) * a;
sum = sum + a/x; x++;
}
printf("sum=%.3f\n", sum);
return 0;
}