习题2-5
![](http://images0.cnblogs.com/blog/570517/201310/30214930-674295eccea14f78a00c01eacdb10c89.png)
#include<stdio.h> int main(void) { int i,n; double item,sum,flag; flag =1; sum =0; printf("Enter n:"); scanf("%d",&n); for(i=1;i<=n;i++){ item=(flag*i)/(2*i-1); flag=-flag; sum=sum+item; } printf("sum=%f\n",sum); }
#include<stdio.h> int main(void) { int i,n; double item,sum,flag; flag =1; sum =0; printf("Enter n:"); scanf("%d",&n); for(i=1;i<=n;i++){ item=(flag*i)/(2*i-1); flag=-flag; sum=sum+item; } printf("sum=%f\n",sum); }