[C++] 문자열 뒤집는 방법

1. reverse() 함수 <algorithm>

#include <algorithm> 
#include<iostream>
#include<string>
using namespace std; 
int main() 
{ 
    string str = "abcd"; 
    reverse(str.begin(), str.end()); 
	cout<<"\n"<<str; 
    return 0;
}

1.5 reverse iterator 사용

string str, rstr;
cin >> str;
rstr.assign(str.rbegin(), str.rend());

2. strrev() 함수 <cstring>

#include<iostream>
#include<cstring>
using namespace std; 
int main() 
{ 
    char str[] ="abcd"; 
    strrev(str);
	cout<<"\n"<<str; 
    return 0;
}

3. for문 사용

#include<iostream>
#include<string>
using namespace std; 
int main() 
{ 
    string str="abcd"; 
    int i;
    
    for(i = str.length() - 1; i >= 0; i--)
    {
      	cout<<str[i];
    }
    return 0;
}

4. 투포인터 사용

#include <iostream>
#include <string>

void reverseString(std::string& str) {
    int left = 0;
    int right = str.length() - 1;

    while (left < right) {
        std::swap(str[left], str[right]);
        left++;
        right--;
    }
}

int main() {
    std::string str = "Hello, World!";
    reverseString(str);
    std::cout << str << std::endl;
    return 0;
}

5. 재귀함수

#include <iostream>
#include <string>

std::string reverseStringRecursive(const std::string& str) {
    if (str.length() <= 1) {
        return str;
    } else {
        return reverseStringRecursive(str.substr(1)) + str[0];
    }
}

int main() {
    std::string str = "Hello, World!";
    std::string reversedStr = reverseStringRecursive(str);
    std::cout << reversedStr << std::endl;
    return 0;
}

 

Reverse String in C++ | DigitalOcean

Different Ways to Reverse a String in C++ - DEV Community