c++ Program to reverse the sentence

C++ Program to reverse the sentence

Input- "My name is Nikhil"
Output "Nikhil is name My"


Here the idea to reverse each word in 1st phase and in 2nd phase reverse the whole sentence.

#include<bits/stdc++.h>

using namespace std;

int main()
{
    string s;
    getline(cin,s);

    cout<<s<<endl;


    int l=s.size();

    int pre=0;
    for(int i=0;i<l;i++)
    {
      if(s[i]==' ')
      {
        int k=i-1;
        while(pre<k){char c=s[pre]; s[pre]=s[k]; s[k]=c; pre++; k--; }

        pre=i+1;
      }
      else if(i==l-1)
      {
        int k=i;
        while(pre<k){char c=s[pre]; s[pre]=s[k]; s[k]=c; pre++; k--; }
      }
    }

    int bck=0;
    int nxt=l-1;

    while(bck<nxt)
    {
     char c=s[bck];
     s[bck]=s[nxt];
     s[nxt]=c;

     nxt--; bck++;
    }

    cout<<s<<endl;

    return 0;
}