求和

题目：// s=1-1/2+1/3-1/4+1/5-1/6...+1/19

下面就是C语言代码

#include<stdio.h>
int main(){
	double s =0;
	int i = 1;
	while(i<= 19 ){
		printf("%d \n",i);
		if(i%2 == 0){
			s -= 1.0/i;
		}else{
			s += 1.0/i;	
		}
		i++;
	}
   printf("s=%f \n",s);
	
   return 0;
} 

运行结果