View Code of Problem 71

# include<stdio.h>
int main(void)
{
    int n,i,t;
    scanf("%d",&n);
    float a=2,b=1,sum=0;
    for(i=0;i<n;++i)
    {
        sum = sum + a/b;
        t = a;
        a = a + b;
        b = t;
    }
    printf("%.2f",sum);
    return 0;
}