Check if a given string is made up of two alternating characters in C++

Here we will see how to check a string is made up of alternating characters or not. If a string is like XYXYXY, it is valid, if a string is like ABCD, that is invalid.

The approach is simple. We will check whether all ith character and i+2 th character are same or not. if they are not same, then return false, otherwise return true.

Example

 Live Demo

#include <iostream> using namespace std; bool hasAlternateChars(string str){    for (int i = 0; i < str.length() - 2; i++) {       if (str[i] != str[i + 2]) {          return false;       }    }      if (str[0] == str[1])    return false;      return true; } int main() {    string str = "XYXYXYX";    if(hasAlternateChars(str)){       cout << "Valid String";    }else{       cout << "Not a Valid String";    } }

Output

Valid String