Program to reverse a sentence words stored as character array in C++

Suppose we have one input string sentence where each element is stored as single character, we have to reverse the strings word by word.

So, if the input is like ["t","h","e"," ","m","a","n"," ","i","s"," ","n","l","c","e"], then the output will be ["n","l","c","e"," ","i","s"," ","m","a","n"," ","t","h","e"]

To solve this, we will follow these steps −

• reverse the array s

• j := 0

• n := size of s

• for initialize i := 0, when i < n, update (increase i by 1), do −

  • if s[i] is same as ' ', then −

    • reverse the array s from index j to i

    • j := i + 1

• reverse the array s from index j to n

Let us see the following implementation to get better understanding −

Example

 Live Demo

#include <bits/stdc++.h> using namespace std; void print_vector(vector<auto> v){    cout << "[";    for(int i = 0; i<v.size(); i++){       cout << v[i] << ", ";    }    cout << "]"<<endl; } class Solution {    public:    void reverseWords(vector<char>& s) {       reverse(s.begin(), s.end());       int j = 0;       int n = s.size();       for(int i = 0; i < n; i++){          if(s[i] == ' '){             reverse(s.begin() + j, s.begin() + i);             j = i + 1;          }       }       reverse(s.begin() + j, s.begin() + n);    } }; main(){    Solution ob;    vector<char> v = {'t','h','e',' ','m','a','n',' ','i','s','    ','n','i','c','e'};    ob.reverseWords(v);    print_vector(v); }

Input

{'t','h','e',' ','m','a','n',' ','i','s',' ','n','i','c','e'}

Output

[n, i, c, e, , i, s, , m, a, n, , t, h, e, ]