Šešioliktainiai skaičiai 2017.1

//2017 1 užduotis. Šešioliktainiai skaičiai VS
#include <fstream>
#include <string>

using namespace std;

void reading(int &a, int &b, int red[], int green[], int blue[]);
string rgb_to_hex(int red[], int green[], int blue[], int numb);
void writing(int a, int b, int red[], int green[], int blue[]);
string rgb_hex(int value);
char simbol(int f);

int main() {
    int a, b;
    int red[10000], green[10000], blue[10000];


    reading(a, b, red, green, blue);
    writing(a, b, red, green, blue);

    getchar();
    return 0;
}


void reading(int &a, int &b, int red[], int green[], int blue[]) {
    ifstream input;

    input.open("U1.txt");

    input >> a >> b;
    for (int x = 0; x < a*b; x++) {
        input >> red[x];
        input >> green[x];
        input >> blue[x];
    }

    input.close();
}

void writing(int a, int b, int red[], int green[], int blue[]) {
    ofstream output;

    output.open("U1rez.txt");

    for (int x = 0; x < a*b; x++) {
        output << rgb_to_hex(red, green, blue, x) << ";";
        if ((x+1) % 3 == 0) output << endl;
    }

    output.close();
}

string rgb_to_hex(int red[], int green[], int blue[], int numb) {
    string final = "";

    final += rgb_hex(red[numb])[0]; //hard way because of vs
    final += rgb_hex(red[numb])[1];
    final += rgb_hex(green[numb])[0];
    final += rgb_hex(green[numb])[1];
    final += rgb_hex(blue[numb])[0];
    final += rgb_hex(blue[numb])[1];

    return final;
    //return rgb_hex(red[numb]) + rgb_hex(green[numb]) + rgb_hex(blue[numb]);
}

string rgb_hex(int value) {
    int f, s;
    char pair_c[2];

    f = value / 16;
    s = value % 16;

    pair_c[0] = simbol(f);
    pair_c[1] = simbol(s);

    return pair_c;
}


char simbol(int f) {
    if (f == 0) return '0';
    else if (f == 1) return '1';
    else if (f == 2) return '2';
    else if (f == 3) return '3';
    else if (f == 4) return '4';
    else if (f == 5) return '5';
    else if (f == 6) return '6';
    else if (f == 7) return '7';
    else if (f == 8) return '8';
    else if (f == 9) return '9';
    else if (f == 10) return 'a';
    else if (f == 11) return 'b';
    else if (f == 12) return 'c';
    else if (f == 13) return 'd';
    else if (f == 14) return 'e';
    else if (f == 15) return 'f';
}