CPP

c++ char to uppercase

char choice; 
// it will instantly transform it to upper case without the need
// to convert it to int first
choice = (char)toupper(choice);

convert all characters in string to uppercase c++

transform(str.begin(), str.end(), str.begin(), ::toupper); 

convert letters to uppercase in c++

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

int main()
{
    char letter;

    cout << "You will be asked to enter a character.";
    cout << "
If it is a lowercase character, it will be converted to uppercase.";
    cout << "

Enter a character. Press . to stop: ";

    cin >> letter;

    if(islower(letter))
    {
        letter = isupper(letter);
        cout << letter;
    }

    while(letter != '.')
    {
        cout << "

Enter a character. Press . to stop: ";
        cin >> letter;

        if(islower(letter))
        {
            letter = toupper(letter);
            cout << letter;
        }
    }

    return 0;
}