codevs——3064 求和

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
double x;
double ans;
int read()
{
    int x=0,f=1;   char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘) f=-1;  ch=getchar(); }
    while(ch<=‘9‘&&ch>=‘0‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
int main()
{
    x=read();
    long long n=1;
    while(n<=5000000)
    {
        ans+=1.0/n;
        if(ans>x)
        {    
            printf("%d",n);
            return 0;
        }         
        n++;
    }
    printf("Error!\n");
    return 0;
}