reverseStringUsingStack.cpp

#include<iostream>
#include<string>
#include<stack>

using namespace std;

//------------------------USING STACK-------------------- takes Time coplexity=O(n),space complexity=O(n) due to space allocated for stack

//void reverse(string str) {
//	stack<char> s;
//	
//	//push string to stack
//	//reading the string char one by one and pusing it to stack
//	for(int i=0;i<str.length();i++) {
//		s.push(str[i]);
//	}
//	
//	//popping the chars and revrrsing
//	for(int i=0; i<str.length();i++) {
//		str[i] = s.top(); //storing top element of stack in str,reversal
//		s.pop(); //popping
//	}
//	cout<<str; //string is now updated and reversed
//}

//int main() {
//	string name;
//	getline(cin,name);
//	reverse(name);
//	
//	return 0;
//}

//TIME COMPLEXITY=o(n) AND SPACE COMPLEXITY= O(1) , n = size of string for the below method

void reverse(string str) {
	
	int i = 0;
	int j = str.length()-1;
	
	
//	if(i==j) {
//		return;
//	}
	
	while(i<j) {
		
		swap(str[i],str[j]); //swapping 
		i++;
		j--;
	}
	
	cout<<str; //now str is updated with new reversed value	
}

int main() {
	string name;
	getline(cin,name);
	reverse(name);
	
	return 0;
}