c语言题目，求大神解答c++

Question

Answer 1

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