Check if a string represents a hexadecimal number or not

Last Updated : 23 Nov, 2023

Given an alphanumeric string S of length N, the task is to check if the given string represents a hexadecimal number or not. Print Yes if it represents a hexadecimal number. Otherwise, print No.

Examples:

Input: S = “BF57C”
Output: Yes
Explanation:
Decimal Representation of the given string = 783740

Input: S = “58GK”
Output: No

Approach: The approach is based on the idea that all the elements of a hexadecimal number lie between characters A to F or between integers 0 to 9. Below are the steps to solve the problem:

Iterate over the given string.
Check if each character of the string is between characters A to F or between 0 and 9.
If found to be true, then print Yes.
Otherwise, print No.

Below is the implementation of the above approach:

C++

// C++ implementation of the above approach 
#include <bits/stdc++.h> 
using namespace std; 
 
// Function to check if the string 
// represents a hexadecimal number 
void checkHex(string s) 
{ 
     
    // Size of string 
    int n = s.length(); 
 
    // Iterate over string 
    for(int i = 0; i < n; i++) 
    { 
        char ch = s[i]; 
 
        // Check if the character 
        // is invalid 
        if ((ch < '0' || ch > '9') && 
            (ch < 'A' || ch > 'F')) 
        { 
            cout << "No" << endl; 
            return; 
        } 
    } 
 
    // Print true if all 
    // characters are valid 
    cout << "Yes" << endl; 
} 
 
// Driver code     
int main() 
{ 
     
    // Given string 
    string s = "BF57C"; 
 
    // Function call 
    checkHex(s); 
 
    return 0; 
} 
 
// This code is contributed by divyeshrabadiya07

Java

// Java implementation of the above approach
 
import java.util.*;
import java.io.*;
 
class GFG {
 
    // Function to check if the string
    // represents a hexadecimal number
    public static void checkHex(String s)
    {
        // Size of string
        int n = s.length();
 
        // Iterate over string
        for (int i = 0; i < n; i++) {
 
            char ch = s.charAt(i);
 
            // Check if the character
            // is invalid
            if ((ch < '0' || ch > '9')
                && (ch < 'A' || ch > 'F')) {
 
                System.out.println("No");
                return;
            }
        }
 
        // Print true if all
        // characters are valid
        System.out.println("Yes");
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        // Given string
        String s = "BF57C";
 
        // Function Call
        checkHex(s);
    }
}

Python3

# Python3 implementation of the
# above approach 
 
# Function to check if the string
# represents a hexadecimal number
def checkHex(s):
   
    # Iterate over string
    for ch in s:
 
        # Check if the character
        # is invalid
        if ((ch < '0' or ch > '9') and
            (ch < 'A' or ch > 'F')):
                 
            print("No")
            return
         
    # Print true if all
    # characters are valid
    print("Yes")
 
# Driver Code
     
# Given string
s = "BF57C"
  
# Function call
checkHex(s)
 
# This code is contributed by extragornax

C#

// C# implementation of 
// the above approach
using System;
class GFG{
 
// Function to check if the string
// represents a hexadecimal number
public static void checkHex(String s)
{
  // Size of string
  int n = s.Length;
 
  // Iterate over string
  for (int i = 0; i < n; i++) 
  {
    char ch = s[i];
 
    // Check if the character
    // is invalid
    if ((ch < '0' || ch > '9') && 
        (ch < 'A' || ch > 'F')) 
    {
      Console.WriteLine("No");
      return;
    }
  }
 
  // Print true if all
  // characters are valid
  Console.WriteLine("Yes");
}
 
// Driver Code
public static void Main(String[] args)
{
  // Given string
  String s = "BF57C";
 
  // Function Call
  checkHex(s);
}
}
 
// This code is contributed by gauravrajput1

Javascript

<script>
 
// JavaScript implementation of the 
// above approach
 
// Function to check if the string
// represents a hexadecimal number
function checkHex(s)
{
     
    // Size of string
    let n = s.length;
 
    // Iterate over string
    for(let i = 0; i < n; i++) 
    {
        let ch = s[i];
 
        // Check if the character
        // is invalid
        if ((ch < '0' || ch > '9') && 
            (ch < 'A' || ch > 'F')) 
        {
            document.write("No");
            return;
        }
    }
 
    // Print true if all
    // characters are valid
    document.write("Yes");
}
 
// Driver code
 
// Given string
let s = "BF57C";
 
// Function Call
checkHex(s);
 
// This code is contributed by souravghosh0416
 
</script>

Output

Yes

Time Complexity: O(N)
Auxiliary Space: O(1)

Approach 2:

Approach:

We can use the built-in function int() with a base of 16 to convert the string to a hexadecimal number. If the conversion is successful, the input string represents a hexadecimal number.

The input string s is passed as a parameter to the function.
The int() function is called with the input string s and a base of 16 as its parameters. This function converts a string representation of a number into an integer.
If the conversion is successful, the function returns True, indicating that the input string represents a hexadecimal number.
If the conversion raises a ValueError, the function returns False, indicating that the input string does not represent a hexadecimal number. The ValueError is raised when the input string contains characters that are not valid hexadecimal digits.

C++

#include <iostream>
#include <string>
#include <sstream>
 
bool isHexadecimal(const std::string& s) {
    try {
        // Attempt to parse the string as an integer in base 16 (hexadecimal)
        std::istringstream stream(s);
        unsigned int value;
        stream >> std::hex >> value;
        return !stream.fail(); // If successful, the string is hexadecimal
    } catch (std::exception& e) {
        return false; // If an exception is caught, the string is not hexadecimal
    }
}
 
int main() {
    std::string s1 = "BF57C";
    if (isHexadecimal(s1)) {
        std::cout << "Yes" << std::endl;
        std::istringstream stream(s1);
        unsigned int value;
        stream >> std::hex >> value;
        std::cout << "Decimal Representation of the given string = " << value << std::endl;
    } else {
        std::cout << "No" << std::endl;
    }
 
    std::string s2 = "58GK";
    if (isHexadecimal(s2)) {
        std::cout << "Yes" << std::endl;
        std::istringstream stream(s2);
        unsigned int value;
        stream >> std::hex >> value;
        std::cout << "Decimal Representation of the given string = " << value << std::endl;
    } else {
        std::cout << "No" << std::endl;
    }
 
    return 0;
}

Java

public class HexadecimalValidator {
    // Function to check if a string is a valid hexadecimal representation
    public static boolean isHexadecimal(String s) {
        try {
            // Attempt to parse the string as an integer in base 16 (hexadecimal)
            Integer.parseInt(s, 16);
            return true; // If successful, the string is hexadecimal
        } catch (NumberFormatException e) {
            return false; // If an exception is caught, the string is not hexadecimal
        }
    }
 
    public static void main(String[] args) {
        String s1 = "BF57C";
        if (isHexadecimal(s1)) {
            System.out.println("Yes");
            System.out.println("Decimal Representation of the given string = " + Integer.parseInt(s1, 16));
        } else {
            System.out.println("No");
        }
 
        String s2 = "58GK";
        if (isHexadecimal(s2)) {
            System.out.println("Yes");
            System.out.println("Decimal Representation of the given string = " + Integer.parseInt(s2, 16));
        } else {
            System.out.println("No");
        }
    }
}

Python3

def is_hexadecimal_1(s):
    try:
        int(s, 16)
        return True
    except ValueError:
        return False
 
s1 = "BF57C"
if is_hexadecimal_1(s1):
    print("Yes")
    print("Decimal Representation of the given string = {}".format(int(s1, 16)))
else:
    print("No")
 
s2 = "58GK"
if is_hexadecimal_1(s2):
    print("Yes")
    print("Decimal Representation of the given string = {}".format(int(s2, 16)))
else:
    print("No")

C#

// C# code for the above approach
using System;
 
public class GFG {
    // Function to check if a string is in hexadecimal
    // format
    public static bool IsHexadecimal(string s)
    {
        try {
            // Attempt to parse the string as an integer in
            // base 16 (hexadecimal)
            _ = Convert.ToInt32(s, 16);
            return true; // If successful, the string is
                         // hexadecimal
        }
        catch (Exception) {
            return false; // If an exception is caught, the
                          // string is not hexadecimal
        }
    }
 
    // Main method
    public static void Main(string[] args)
    {
        string s1 = "BF57C";
        if (IsHexadecimal(s1)) {
            Console.WriteLine("Yes");
            int value = Convert.ToInt32(s1, 16);
            Console.WriteLine(
                "Decimal Representation of the given string = "
                + value);
        }
        else {
            Console.WriteLine("No");
        }
 
        string s2 = "58GK";
        if (IsHexadecimal(s2)) {
            Console.WriteLine("Yes");
            int value = Convert.ToInt32(s2, 16);
            Console.WriteLine(
                "Decimal Representation of the given string = "
                + value);
        }
        else {
            Console.WriteLine("No");
        }
    }
}
 
// This code is contributed by Susobhan Akhuli

Javascript

function isHexadecimal(s) {
    try {
        // Attempt to parse the string as an integer in base 16 (hexadecimal)
        let value = parseInt(s, 16);
        return !isNaN(value); // If successful, the string is hexadecimal
    } catch (e) {
        return false; // If an exception is caught, the string is not hexadecimal
    }
}
 
let s1 = "BF57C";
if (isHexadecimal(s1)) {
    console.log("Yes");
    let value = parseInt(s1, 16);
    console.log("Decimal Representation of the given string =", value);
} else {
    console.log("No");
}
 
let s2 = "58GK";
if (isHexadecimal(s2)) {
    console.log("Yes");
    let value = parseInt(s2, 16);
    console.log("Decimal Representation of the given string =", value);
} else {
    console.log("No");
}

Output

Yes
Decimal Representation of the given string = 783740
No

Time Complexity: O(n)
Space Complexity: O(1)

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Article Tags :

Practice Tags :

Check if a string represents a hexadecimal number or not

C++

Java

Python3

C#

Javascript

Approach 2:

C++

Java

Python3

C#

Javascript

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