Recursion: Given a string, find the occurrence of first uppercase letter in the string.

Coding Interview Questions

1 min read

Problem Statement:

You are given a string, you need to find the first upper case letter using recursion.

Example:

Input: proDeveloperTutorial
Output: D

Solution Explanation:

We recursively traverse the string, and if any uppercase is found then return the character.

Time Complexity: O(N)
Space Complexity: O(N) for stack call

Code Solution

#include <iostream>
#include <stack>
using namespace std; 

char firstUpperChar(string str, int i)
{
    if (str[i] == '\0')
         return 0;

    if (isupper(str[i])) 
            return str[i];
            
    return firstUpperChar(str, i+1);
}

int main()
{
    string str = "proDeveloperTutorial";
    char result = firstUpperChar(str, 0);

    if (result == 0)
        cout << "No uppercase letter";
    else
        cout << result << "\n";
    return 0;
}