Zzuli:1041 sum of sequence 2

Title Description

Enter an integer n, Output sequence 1-1/3+1/5-…… front n Sum of items .

Input

Enter only one integer n.

Output

The result is reserved 2 Is a decimal , Take a line alone .

The sample input Copy

3

Sample output Copy

0.87

#include <stdio.h>
int main()
{
	int n,i,sign=1;
	double t,term,sum=1,deno=3;
	scanf("%d",&n);
	if(n!=0)
	{
	for(i=1;i<n;i++)
	{
		t=1/deno;
		sign=(-1)*sign;
		term=sign*t;
		deno=deno+2;
		sum=sum+term;
	}
	printf("%.2lf",sum);}
	else
	printf("0.00");
	return 0;
}