将给定的RGB颜色代码转换为十六进制颜色代码

给定R ， G和B这三种颜色，请将RGB颜色转换为十六进制颜色代码。如果无法进行转换，则打印-1。

例子：

Input: R = 0, G = 0, B = 0
Output: #000000

Input: R = 255, G = 255, B = 256
Output: -1
Explanation:
256 color code is not possible as only 0-255 range is available for a color.

方法：

1. 首先检查每种给定的颜色是否在0-255之间。
2. 如果不是，则打印-1并退出程序，因为在这种情况下无法进行转换。
3. 如果它们在范围内，则对于每种颜色，将给定的颜色代码转换为其等效的十六进制数字。
4. 如果十六进制值为1位数，请在左侧加0以使其为2位数。
5. 然后在最终答案中，在开头添加“＃”，然后分别添加R，G和B的十六进制值。

下面是上述方法的实现。

C++

// C++ code to convert the given RGB
// color code to Hex color code
  
#include 
using namespace std;
  
// function to convert decimal to hexadecimal
string decToHexa(int n)
{
    // char array to store hexadecimal number
    char hexaDeciNum[2];
  
    // counter for hexadecimal number array
    int i = 0;
    while (n != 0) {
  
        // temporary variable to store remainder
        int temp = 0;
  
        // storing remainder in temp variable.
        temp = n % 16;
  
        // check if temp < 10
        if (temp < 10) {
            hexaDeciNum[i] = temp + 48;
            i++;
        }
        else {
            hexaDeciNum[i] = temp + 55;
            i++;
        }
  
        n = n / 16;
    }
  
    string hexCode = "";
    if (i == 2) {
        hexCode.push_back(hexaDeciNum[0]);
        hexCode.push_back(hexaDeciNum[1]);
    }
    else if (i == 1) {
        hexCode = "0";
        hexCode.push_back(hexaDeciNum[0]);
    }
    else if (i == 0)
        hexCode = "00";
  
    // Return the equivalent
    // hexadecimal color code
    return hexCode;
}
  
// Function to convert the
// RGB code to Hex color code
string convertRGBtoHex(int R, int G, int B)
{
    if ((R >= 0 && R <= 255)
        && (G >= 0 && G <= 255)
        && (B >= 0 && B <= 255)) {
  
        string hexCode = "#";
        hexCode += decToHexa(R);
        hexCode += decToHexa(G);
        hexCode += decToHexa(B);
  
        return hexCode;
    }
  
    // The hex color code doesn't exist
    else
        return "-1";
}
  
// Driver program to test above function
int main()
{
    int R = 0, G = 0, B = 0;
    cout << convertRGBtoHex(R, G, B) << endl;
  
    R = 255, G = 255, B = 255;
    cout << convertRGBtoHex(R, G, B) << endl;
  
    R = 25, G = 56, B = 123;
    cout << convertRGBtoHex(R, G, B) << endl;
  
    R = 2, G = 3, B = 4;
    cout << convertRGBtoHex(R, G, B) << endl;
  
    R = 255, G = 255, B = 256;
    cout << convertRGBtoHex(R, G, B) << endl;
  
    return 0;
}

Java

// Java code to convert the given RGB
// color code to Hex color code
   
  
import java.util.*;
  
class GFG{
   
// function to convert decimal to hexadecimal
static String decToHexa(int n)
{
    // char array to store hexadecimal number
    char []hexaDeciNum = new char[2];
   
    // counter for hexadecimal number array
    int i = 0;
    while (n != 0) {
   
        // temporary variable to store remainder
        int temp = 0;
   
        // storing remainder in temp variable.
        temp = n % 16;
   
        // check if temp < 10
        if (temp < 10) {
            hexaDeciNum[i] = (char) (temp + 48);
            i++;
        }
        else {
            hexaDeciNum[i] = (char) (temp + 55);
            i++;
        }
   
        n = n / 16;
    }
   
    String hexCode = "";
    if (i == 2) {
        hexCode+=hexaDeciNum[0];
        hexCode+=hexaDeciNum[1];
    }
    else if (i == 1) {
        hexCode = "0";
        hexCode+=hexaDeciNum[0];
    }
    else if (i == 0)
        hexCode = "00";
   
    // Return the equivalent
    // hexadecimal color code
    return hexCode;
}
   
// Function to convert the
// RGB code to Hex color code
static String convertRGBtoHex(int R, int G, int B)
{
    if ((R >= 0 && R <= 255)
        && (G >= 0 && G <= 255)
        && (B >= 0 && B <= 255)) {
   
        String hexCode = "#";
        hexCode += decToHexa(R);
        hexCode += decToHexa(G);
        hexCode += decToHexa(B);
   
        return hexCode;
    }
   
    // The hex color code doesn't exist
    else
        return "-1";
}
   
// Driver program to test above function
public static void main(String[] args)
{
    int R = 0, G = 0, B = 0;
    System.out.print(convertRGBtoHex(R, G, B) +"\n");
   
    R = 255; G = 255; B = 255;
    System.out.print(convertRGBtoHex(R, G, B) +"\n");
   
    R = 25; G = 56; B = 123;
    System.out.print(convertRGBtoHex(R, G, B) +"\n");
   
    R = 2; G = 3; B = 4;
    System.out.print(convertRGBtoHex(R, G, B) +"\n");
   
    R = 255; G = 255; B = 256;
    System.out.print(convertRGBtoHex(R, G, B) +"\n");
   
}
}
  
// This code is contributed by 29AjayKumar

Python3

# Python3 program to convert the given 
# RGB color code to Hex color code 
  
# Function to convert decimal to hexadecimal 
def decToHexa(n): 
  
    # char array to store hexadecimal number 
    hexaDeciNum = ['0'] * 100
  
    # Counter for hexadecimal number array 
    i = 0
      
    while (n != 0): 
  
        # Temporary variable to store remainder 
        temp = 0
  
        # Storing remainder in temp variable. 
        temp = n % 16
  
        # Check if temp < 10 
        if (temp < 10): 
            hexaDeciNum[i] = chr(temp + 48)
            i = i + 1
  
        else: 
            hexaDeciNum[i] = chr(temp + 55)
            i = i + 1
  
        n = int(n / 16)
  
    hexCode = ""
    if (i == 2):
        hexCode = hexCode + hexaDeciNum[0] 
        hexCode = hexCode + hexaDeciNum[1] 
  
    elif (i == 1): 
        hexCode = "0"
        hexCode = hexCode + hexaDeciNum[0]
  
    elif (i == 0):
        hexCode = "00"
  
    # Return the equivalent 
    # hexadecimal color code 
    return hexCode
  
# Function to convert the 
# RGB code to Hex color code 
def convertRGBtoHex(R, G, B): 
  
    if ((R >= 0 and R <= 255) and
        (G >= 0 and G <= 255) and
        (B >= 0 and B <= 255)): 
  
        hexCode = "#"; 
        hexCode = hexCode + decToHexa(R)
        hexCode = hexCode + decToHexa(G) 
        hexCode = hexCode + decToHexa(B) 
        return hexCode
  
    # The hex color code doesn't exist 
    else:
        return "-1"
  
# Driver Code
R = 0
G = 0
B = 0
print (convertRGBtoHex(R, G, B)) 
  
R = 255
G = 255
B = 255
print (convertRGBtoHex(R, G, B))
  
R = 25
G = 56
B = 123
print (convertRGBtoHex(R, G, B))
  
R = 2
G = 3
B = 4
print (convertRGBtoHex(R, G, B))
  
R = 255
G = 255
B = 256
print (convertRGBtoHex(R, G, B))
  
# This code is contributed by Pratik Basu

C#

// C# code to convert the given RGB
// color code to Hex color code
using System;
  
class GFG{
  
// Function to convert decimal 
// to hexadecimal
static string decToHexa(int n)
{
      
    // char array to store 
    // hexadecimal number
    char []hexaDeciNum = new char[2];
  
    // Counter for hexadecimal 
    // number array
    int i = 0;
    while (n != 0)
    {
  
        // Temporary variable to
        // store remainder
        int temp = 0;
  
        // Storing remainder in 
        // temp variable.
        temp = n % 16;
  
        // Check if temp < 10
        if (temp < 10) 
        {
            hexaDeciNum[i] = (char) (temp + 48);
            i++;
        }
        else 
        {
            hexaDeciNum[i] = (char) (temp + 55);
            i++;
        }
        n = n / 16;
    }
    string hexCode = "";
      
    if (i == 2)
    {
        hexCode += hexaDeciNum[0];
        hexCode += hexaDeciNum[1];
    }
    else if (i == 1)
    {
        hexCode = "0";
        hexCode += hexaDeciNum[0];
    }
    else if (i == 0)
        hexCode = "00";
  
    // Return the equivalent
    // hexadecimal color code
    return hexCode;
}
  
// Function to convert the
// RGB code to Hex color code
static string convertRGBtoHex(int R, int G,
                                     int B)
{
    if ((R >= 0 && R <= 255) && 
        (G >= 0 && G <= 255) && 
        (B >= 0 && B <= 255)) 
    {
        string hexCode = "#";
        hexCode += decToHexa(R);
        hexCode += decToHexa(G);
        hexCode += decToHexa(B);
  
        return hexCode;
    }
  
    // The hex color code doesn't exist
    else
        return "-1";
}
  
// Driver code
public static void Main(string[] args)
{
    int R = 0, G = 0, B = 0;
    Console.Write(convertRGBtoHex(R, G, B) + "\n");
  
    R = 255; G = 255; B = 255;
    Console.Write(convertRGBtoHex(R, G, B) + "\n");
  
    R = 25; G = 56; B = 123;
    Console.Write(convertRGBtoHex(R, G, B) + "\n");
  
    R = 2; G = 3; B = 4;
    Console.Write(convertRGBtoHex(R, G, B) + "\n");
  
    R = 255; G = 255; B = 256;
    Console.Write(convertRGBtoHex(R, G, B) + "\n");
}
}
  
// This code is contributed by rutvik_56

输出：

#000000
#FFFFFF
#9183B7
#020304
-1