PTA | 习题2-4 求交错序列前N项和 (15分)

    int i;
    double sum=0.0;
    int t1=1;
    int t2=1;
    int temp=1;
    for(i=1;i<=n;i++)
    {
        sum+=((double)t1/t2)*temp;
        t1++;
        t2+=2;
        temp=-temp;
    }

#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    int i;
    if(n!=0){
    double sum=0.0;
    int t1=1;
    int t2=1;
    int temp=1;
    for(i=1;i<=n;i++)
    {
        sum+=((double)t1/t2)*temp;
        t1++;
        t2+=2;
        temp=-temp;
    }
    printf("%.3lf\n",sum);
    }
    return 0;
}