StringToLowerAndUpperExample

#include <iostream>
#include <string>

int main(){


    std::string text = "The QuiCk BroWN FOX"; /// Some string

    for(int i = 0; i < text.size(); i++){ /// for loop that takes string.size() and for each iteration
        text[i] = tolower(text[i]);       /// will get the current letter at index i inside the string text
     }                                    /// and replace it with the same letter in lowercase

    std::cout << text << std::endl;     ///print in lowercase

    for (char& letter : text){          /// The same can be done with foreach loop (since C++11)
        letter = toupper(letter);       /// in this example we are changing the text to uppercase
    }                                   /// char& letter -> is used in order to take the letter by refrence
                                        /// which means by address in the memory so it will be
                                        /// changed if we don't take it like that we will change a copy

    std::cout << text << std::endl;     /// Prints the text in uppercase

    /// There are many more ways to do that check on google.com!

    return 0;
}