to_string()的应用

作用是将数字转化为字符串

#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<map>
#include<cstdlib>
#include<set>
#include<ctime>
#include<vector>
#include<cstdio>
#include<list>
using namespace std;
typedef long long ll;
int INF=;
int inf=-;
#define read(x) scanf("%d",&x);
#define fo(i,n) for(int i=1;i<=(n);i++)
#define me(a) memset(a,0,sizeof(a));
#define one(x) cout<<(x)<<endl;
#define two(a,b) cout<<(a)<<" "<<(b)<<endl;
int main()
{
    int n;
    string s;
    for(int i=;i<=;i++)
    {
        s+=to_string(i);
    }
    cin>>n;
    one(s[n-]);
    return ;
}