String Character Shift

• Given a string $S$ of length $N$, shift each character of the string by $K$ positions to the right, where $K\le N$.

For example: Say $S$ = "hacker" and $K=2$. Here $N=6$.
Shifting each character in $S$ by $2$ positions to the right would result into $erhack$.
Note that $S\left[0\right]$ i.e. 'h' is moved by 2 positions to the $S\left[2\right]$. Also, $S\left[5\right]$ i.e. 'r', which is the last character in $S$ comes round-about back to $S\left[1\right]$ as there is no space for 'r' to go beyond the limits of string length.

Approach:

• Declare another auxillary string $shiftedS$ that is of the same size as $S$.
• Copy $i^{th}$ element of $S$ to the $(K+i{)}^{th}$ position in $shiftedS$. This means, $shiftedS[i+K]=S\left[i\right]$ where $0\le i<N$.
• Make sure that $i+K$ never exceeds $N$, because that will try to access a memory location which is not declared in $shiftedS$. There's a simple trick to ensure that - use $(i+K)modN$ .

#include <iostream>

#include<string>

using namespace std;

int main()

{

    string s,p;

    cin>>s;

    int k;

    cin>>k;

    for(int i=0;i<s.size();i++)

    {

        int index=(i+k)%s.size();

        p[index]=s[i];

        

    }

  for(int i=0;i<s.size();i++) { cout<<p[i];}