How to validate CVV number using Regular Expression

Last Updated : 21 Dec, 2022

Given string str, the task is to check whether it is a valid CVV (Card Verification Value) number or not by using Regular Expression.
The valid CVV (Card Verification Value) number must satisfy the following conditions:

It should have 3 or 4 digits.
It should have a digit between 0-9.
It should not have any alphabet or special characters.

Examples:

Input: str = “561”
Output: true
Explanation:
The given string satisfies all the above mentioned conditions. Therefore, it is a valid CVV (Card Verification Value) number.

Input: str = “50614”
Output: false
Explanation:
The given string has five-digit. Therefore, it is not a valid CVV (Card Verification Value) number.

Input: str = “5a#1”
Output: false
Explanation: The given string has alphabets and special characters. Therefore, it is not a valid CVV (Card Verification Value) number.

Approach: The idea is to use Regular Expression to solve this problem. The following steps can be followed to compute the answer.

Get the String.
Create a regular expression to check the valid CVV (Card Verification Value) number as mentioned below:

regex = "^[0-9]{3, 4}$";

Where:
- ^ represents the starting of the string.
- [0-9] represents the digit between 0-9.
- {3, 4} represents the string that has 3 or 4 digits.
- $ represents the ending of the string.
Match the given string with the regular expression. In Java, this can be done by using Pattern.matcher().
Return true if the string matches with the given regular expression, else return false.

Below is the implementation of the above approach:

C++

   // C++ program to validate the
// CVV (Card Verification Value) number
// using Regular Expression
#include <iostream>
#include <regex>
using namespace std;
 
// Function to validate the CVV 
// (Card Verification Value) number
bool isValidCVVNumber(string str)
{
 
    // Regex to check valid CVV 
    // (Card Verification Value) number
    const regex pattern("^[0-9]{3,4}$");
 
    // If the CVV (Card Verification Value)
    //  number is empty return false
    if (str.empty()) 
    {
        return false;
    }
 
    // Return true if the CVV 
    // (Card Verification Value) number 
    // matched the ReGex
    if (regex_match(str, pattern)) 
    {
        return true;
    }
    else
    {
        return false;
    }
}
 
// Driver Code
int main()
{
    // Test Case 1:
    string str1 = "561";
    cout << isValidCVVNumber(str1) << endl;
 
    // Test Case 2:
    string str2 = "5061";
    cout << isValidCVVNumber(str2) << endl;
 
    // Test Case 3:
    string str3 = "50614";
    cout << isValidCVVNumber(str3) << endl;
 
    // Test Case 4:
    string str4 = "5a#1";
    cout << isValidCVVNumber(str4) << endl;
 
    return 0;
}
 
// This code is contributed by yuvraj_chandra
 
  

Java

   // Java program to validate
// CVV (Card Verification Value)
// number using regex.
import java.util.regex.*;
class GFG {
 
    // Function to validate
    // CVV (Card Verification Value) number.
    // using regular expression.
    public static boolean isValidCVVNumber(String str)
    {
        // Regex to check valid CVV number.
        String regex = "^[0-9]{3,4}$";
 
        // Compile the ReGex
        Pattern p = Pattern.compile(regex);
 
        // If the string is empty
        // return false
        if (str == null) 
        {
            return false;
        }
 
        // Find match between given string
        // and regular expression
        // using Pattern.matcher()
 
        Matcher m = p.matcher(str);
 
        // Return if the string
        // matched the ReGex
        return m.matches();
    }
 
    // Driver code
    public static void main(String args[])
    {
 
        // Test Case 1:
        String str1 = "561";
        System.out.println(isValidCVVNumber(str1));
 
        // Test Case 2:
        String str2 = "5061";
        System.out.println(isValidCVVNumber(str2));
 
        // Test Case 3:
        String str3 = "50614";
        System.out.println(isValidCVVNumber(str3));
 
        // Test Case 4:
        String str4 = "5a#1";
        System.out.println(isValidCVVNumber(str4));
    }
}
 
  

Python3

   # Python3 program to validate
# CVV (Card Verification Value)
# number using regex.
import re
 
# Function to validate
# CVV (Card Verification Value) number.
# using regular expression.
 
 
def isValidCVVNumber(str):
 
    # Regex to check valid
    # CVV number.
    regex = "^[0-9]{3,4}$"
 
    # Compile the ReGex
    p = re.compile(regex)
 
    # If the string is empty
    # return false
    if(str == None):
        return False
 
    # Return if the string
    # matched the ReGex
    if(re.search(p, str)):
        return True
    else:
        return False
 
# Driver code
 
 
# Test Case 1:
str1 = "561"
print(isValidCVVNumber(str1))
 
# Test Case 2:
str2 = "5061"
print(isValidCVVNumber(str2))
 
# Test Case 3:
str3 = "50614"
print(isValidCVVNumber(str3))
 
# Test Case 4:
str4 = "5a#1"
print(isValidCVVNumber(str4))
 
# This code is contributed by avanitrachhadiya2155
 
  

C#

   // C# program to validate the
// CVV (Card Verification Value) number
//using Regular Expressions
using System;
using System.Text.RegularExpressions;
class GFG
{
 
// Main Method
static void Main(string[] args)
{
 
    // Input strings to Match
    // CVV (Card Verification Value) number
    string[] str={"561","5061","50614","5a#1"};
    foreach(string s in str) {
    Console.WriteLine( isValidCVVNumber(s) ? "true" : "false");
    }
    Console.ReadKey(); }
 
// method containing the regex
public static bool isValidCVVNumber(string str)
{
    string strRegex = @"^[0-9]{3,4}$";
    Regex re = new Regex(strRegex);
    if (re.IsMatch(str))
    return (true);
    else
    return (false);
}
}
 
// This code is contributed by Rahul Chauhan
 
  

Javascript

   // Javascript program to validate
// CVV Number  using Regular Expression
 
// Function to validate the
// CVV_Number  
function isValid_CVV_Number(CVV_Number) {
    // Regex to check valid
    // CVV_Number  
    let regex = new RegExp(/^[0-9]{3,4}$/);
 
    // if CVV_Number 
    // is empty return false
    if (CVV_Number == null) {
        return "false";
    }
 
    // Return true if the CVV_Number
    // matched the ReGex
    if (regex.test(CVV_Number) == true) {
        return "true";
    }
    else {
        return "false";
    }
}
 
// Driver Code
// Test Case 1:
let str1 = "561";
console.log(isValid_CVV_Number(str1));
 
// Test Case 2:
let str2 = "5061";
console.log(isValid_CVV_Number(str2));
 
// Test Case 3:
let str3 = "50614";
console.log(isValid_CVV_Number(str3));
 
// Test Case 4:
let str4 = "5a#1";
console.log(isValid_CVV_Number(str4));
 
// Test Case 5:
let str5 = "12071998";
console.log(isValid_CVV_Number(str5));
 
// Test Case 6:
let str6 = "RAH12071998";
console.log(isValid_CVV_Number(str6));
 
// This code is contributed by Rahul Chauhan
 
  

Output

true true false false

Time Complexity: O(N) for each testcase, where N is the length of the given string.
Auxiliary Space: O(1)

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How to validate CVV number using Regular Expression

C++

Java

Python3

C#

Javascript

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