#include<bits/stdc++.h>
#include<cstring>
#include<queue>
#include<set>
#include<stack>
#include<vector>
#define ll long long
using namespace std;
const int N=1e5+10;
const int M=2023;
const int inf=0x3f3f3f3f;
int n,m,k;
void dfs(int n)
{
	if(n<=0)return;
	cout<<n%10;
	dfs(n/10);
}
int main()
{
	cin>>n;
	dfs(n);
	return 0;
}

#include<iostream>
using namespace std;
//#define LL long long
//const int N = 1e6 + 10;
//const int INF = 0x3f3f3f3f;
//int a[10][10];
int a;
int main(){
	cin>>a;
	while(a){
		cout<<a%10;
		a/=10;
	}
}

#include 
using namespace std;
int main() 
{
    string n;
    getline(cin, n);
    for (int i = n.size() - 1; i >= 0; i--) 
	{
        cout << n[i];
    }
    return 0;
}

这题很简单，建议用字符串做，不然那个“0”会很麻烦(>ω･* )ﾉ

#include<iostream>
using namespace std;
int main(){
	string a;
	cin>>a;
	for(int i = a.size()-1; i >= 0; i -- ){
		cout<<a[i];
	}
	return 0;
}

#include<stdio.h> #include<iostream> using namespace std; int main() { char a,b,c; cin >>a >>b >>c; cout<< c<< b<< a;

}

递归：

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cmath>
#include<iomanip>
#include<queue>
#include<algorithm>
#include<vector>
#include<stack>
#include<set>
using namespace std;
#define LL long long
const int N=100;
using namespace std;
int f(int n,int m)
{
	f(n%2)
}
int main()
{
	int a,b;
	cin>>a>>b;
	cout<<f(a,b);
	return 0;
}

#include<stdio.h>
int main()
{
    int n,a,b,c;
    scanf("%d",&n);
    a=n/100;
    b=n/10%10;
    c=n%10;
    printf("%d%d%d\n",c,b,a);
    return 0;
}

需要这么难？

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int N=1e7+10;
const int INF=0x3f3f3f3f;
int main()
{
	int a;
	cin>>a;
	cout<<a%10<<a/10%10<<a/100%10;
}

#include<iostream> using namespace std; int main(){ int n; cin>>n; cout<<n%10; cout<<n%100/10; cout<<n/100; return 0;

}

#include<iostream> using namespace std; int main(){ int n; cin>>n; cout<<n%10; cout<<n%100/10; cout<<n/100; return 0;

}

#include<iostream>

using namespace std;

int a[1111];

int main(){ int n;

cin>>n;
for(int i=1;i<=3;i++){
	cout<<n%10;
	n/=10;
}

}

#include<iostream>
using namespace std;
int main(){
	string a;
	cin>>a;
	for(int i = a.size()-1; i >= 0; i -- ){
		cout<<a[i];
	}
	return 0;
}

#include <iostream> 
using namespace std; 
int main()
{ 
    int n; 
    cin>>n; 
    int ge=n%10; 
    int shi=n/10%10; 
    int bai=n/100; 
    cout<<ge<<shi<<bai; 
}

#include <iostream> using namespace std; int main(){ int n; cin>>n; int ge=n%10; int shi=n/10%10; int bai=n/100; cout<<ge<<shi<<bai; }

#include <bits/stdc++.h>

using namespace std;

int main(void)
{
	int a;

	cin >> a;

	int x, y, z;

	x = a % 100 % 10;
	y = (a % 100 - x) / 10;
	z = (a - y * 10 - x) / 100;

	cout << x << y << z;

	return 0;
}

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <string>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <stack>
#include <vector>
using namespace std;
#define long long LL
const int N = 1e6+6;
const int INF = 0x3f3f3f3f;
int main(){
    string s;
    cin >> s;
    for (int i = 2;i>=0;i--){
        cout << s[i];
    }
    return 0;
}

/*****************************************
备注：
******************************************/
#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int main(){
	int n;
	cin>>n;
	int ge=n%10;
	int shi=n/10%10;
	int bai=n/100;
	cout<<ge<<shi<<bai;
	return 0;
}

#include <iostream> #include <cstdio> using namespace std; int main() { int a,b,c,d; cin>>d; a=d/100; b=d%100/10; c=d%10; cout<<c100+b10+a; return 0; }

#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
	int a;
	cin >> a;
	int b,g,s;
	g = a%10;
	b = a/100;
	s = (a/10)%10;
	// int t = s;
	// s = t%10;
	// s = s%10;
	cout << g  << s  << b << endl;

}

#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
	int a;
	cin >> a;
	int x,y,z;
	x = a%10;
	z = a/100;
	y = a/10%10;
	cout << x << y << z << endl;


	
	char a,b,c;
	cin >> a >> b >> c;
	cout << c << b << a  << endl;
}