Reverse Each Word in a String

“Reverse Each Word in a String” is a popular problem of string data structure. Here, we are given a string of words and our task is to write a program to reverse each word in a string.

Example:

INPUT:
HelpMeStudyBro is an Emerging Website
OUTPUT:
orBydutSeMpleH si na gnigremE etisbeW 

This problem can be easily solved using stack. The steps required to reverse each word in a string is as follows:

1. Create an empty character stack and initialize an empty resultant string.
2. Start traversing a string.
3. Push characters of the string in the stack until ‘space character’ appears.
4. Once space character is appeared.  Pop all characters from the stack and concatenate them with resultant string.
5. Concatenate a ‘space character’ afterwards.
6. Repeat steps from 3 to 5 until complete string is scanned.
7. In last, concatenate the remaining word to resultant string from stack.
8. Return the resultant string.

C++ Program to reverse each word in a string is as follows:

/* Program to reverse each word in a string */
#include<bits/stdc++.h>  
using namespace std;  
string reverseWords(string str)
{
    stack<char>st;
    string res = "";
    for(int i = 0 ; i < str.length() ; i++)
    {
        // Push the complete word in the string
        if(str[i] != ' ')
        {
            st.push(str[i]);
        }
        else
        {
            // reverse the word and concatneate to resultant string
            while(!st.empty())
            {
                
                char ch = st.top();
                res=res+ch;
                st.pop();
            }
            res=res+" ";
        }
    }
    // concatenate the last reversed word to string
    while(!st.empty())
    {
        char ch = st.top();
        res=res+ch;
        st.pop();
    }
    return res;
}
int main()  
{
    string str;
    cout<<"Enter a string: ";
    getline(cin,str);
    string res = reverseWords(str);
    cout<<"\nResultant string:\n"<<res<<"\n";
}

OUTPUT:
Enter a string: 
HelpMeStudyBro is an Emerging Website
Resultant string:
orBydutSeMpleH si na gnigremE etisbeW

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