C++ covert lower case to upper case in do while loop

#include <iostream>

using namespace std;

int main()

{

    char colour[4][7] = {
        {'a','m','m','a','n','*','\0'},
        { 'j','e','r','a','s','h','\0'}, 
        {'a','q','a','b','a','#','\0'},
        {'a','j','l','o','u','n','\0'}};

    for (int i = 0; i < 4; i++)
        std::cout << colour[i] << "\n";

    return 0;

}

this is the array i want to covert it to upper case using do while loop any help ??