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Check if a string represents a hexadecimal number or not
• Last Updated : 22 Jan, 2021

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:

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

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the above approach``#include ``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`
Output:
`Yes`

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

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