win32_irodelta.cpp

#include <Windows.h>
#include <iostream>

/* irodelta.cpp sets a new console color without modifying previous text */

void setConsoleColour(unsigned short colour)
{
        static const HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
        std::cout.flush();
        SetConsoleTextAttribute(hOut, colour);
}

int main(int argc, char **argv)
{

    if (argc <= 1)
    {
        if (argv[0])
            std::cout << "Usage: " << argv[0] << " <1 or 2-digit hexadecimal number (FOREGROUND BACKGROUND)>" << '\n';
        else
            std::cout << "Usage: <win32_irodelta.exe> <1 or 2-digit hexadecimal number (FOREGROUND BACKGROUND)>" << '\n';

        std::exit(1);
    }
    char *input = argv[1];
    char a = input[0];
    char b = input[1];
    unsigned short foreground = 0; // 0-15
    unsigned short background = 0; // multiple of 16
    if (a>=65 && a<=70)/*ASCII for A-F -> 10-15*/{
        foreground = a-55;
    } else if (a>=97 && a<=102)/*ASCII for a-f -> 10-15*/{
        foreground = a-87;
    } else if (a>=48 && a <= 57)/*ASCII for 0-9*/{
        foreground = a-48;
    }

    if (b>=65 && b<=70){
        background = (b-55)*16;
    } else if (b>=97 && b<=102){
        background = (b-87)*16;
    } else if (b>=48 && b <= 57){
        background = (b-48)*16;
    }

    if (background!=(foreground*16)){
            setConsoleColour(foreground | background);
    } else {
            std::cout << "Error: First argument cannot have same foreground and background" << '\n';
    }
    return 0;
}