RGB To Hexadecimal

This algorithm converts RGB color model to hexadecimal color code.

• C#
• VB.Net
• C
• C++
• PHP

									struct RGB
{
	unsigned char R;
	unsigned char G;
	unsigned char B;
};

char* AppendString(const char* str1, const char* str2) {
	int str1Len = strlen(str1);
	int str2Len = strlen(str2);
	int strLen = str1Len + str2Len + 1;
	char* str = malloc(strLen);

	for (int i = 0; i < str1Len; i++)
		str[i] = str1[i];

	for (int i = 0; i < str2Len; i++)
		str[(str1Len + i)] = str2[i];

	str[strLen - 1] = '\0';

	return str;
}

char* CharToString(char c) {
	char* str = malloc(2);
	str[0] = c;
	str[1] = '\0';

	return str;
}

char* GetSubString(char* str, int index, int count) {
	int strLen = strlen(str);
	int lastIndex = index + count;

	if (index >= 0 && lastIndex > strLen) return "";

	char* subStr = malloc(count + 1);

	for (int i = 0; i < count; i++) {
		subStr[i] = str[index + i];
	}

	subStr[count] = '\0';

	return subStr;
}

char* InsertString(char* str, int index, char* subStr) {
	char* s = GetSubString(str, 0, index);
	s = AppendString(s, subStr);
	s = AppendString(s, GetSubString(str, index, strlen(str) - index));

	return s;
}

char* DecimalToHexadecimal(int dec) {
	if (dec < 1) return "00";

	int hex = dec;
	char* hexStr = "";

	while (dec > 0)
	{
		hex = dec % 16;

		if (hex < 10)
			hexStr = InsertString(hexStr, 0, CharToString(hex + 48));
		else
			hexStr = InsertString(hexStr, 0, CharToString(hex + 55));

		dec /= 16;
	}

	return hexStr;
}

char* RGBToHexadecimal(struct RGB rgb) {
	char* rs = DecimalToHexadecimal(rgb.R);
	char* gs = DecimalToHexadecimal(rgb.G);
	char* bs = DecimalToHexadecimal(rgb.B);

	return AppendString(AppendString(AppendString("#", rs), gs), bs);
}
								

Example

									struct RGB data = { 82, 0, 87 };
char* value = RGBToHexadecimal(data);
								

Output

									#520057