How to validate CVV number using Regular Expression

11 Nov, 2021
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 alphabets and special characters.
It should have 3 or 4 digits.
It should have a digit between 0-9.
It should not have any alphabets and 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 valid CVV (Card Verification Value) number as mentioned below:
regex = "^[0-9]{3, 4}$";
Where: ^ represents the starting of the string.[0-9] represents the digit between 0-9.{3, 4} represents the string has 3 or 4 digits.$ represents the ending of the string.
^ represents the starting of the string.
[0-9] represents the digit between 0-9.
{3, 4} represents the string 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:
Java
Python3
C++
// 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}$";         // Compile the ReGex        Pattern p = Pattern.compile(regex);         // If the string is empty        // return false        if (str == null)        {            return false;        }         // Find match between given string        // and regular expression        // using Pattern.matcher()         Matcher m = p.matcher(str);         // Return if the string        // matched the ReGex        return m.matches();    }     // Driver code    public static void main(String args[])    {         // Test Case 1:        String str1 = "561";        System.out.println(isValidCVVNumber(str1));         // Test Case 2:        String str2 = "5061";        System.out.println(isValidCVVNumber(str2));         // Test Case 3:        String str3 = "50614";        System.out.println(isValidCVVNumber(str3));         // Test Case 4:        String str4 = "5a#1";        System.out.println(isValidCVVNumber(str4));    }}
# Python3 program to validate# CVV (Card Verification Value)# number using regex.import re # Function to validate# CVV (Card Verification Value) number.# using regular expression.  def isValidCVVNumber(str):     # Regex to check valid    # CVV number.    regex = "^[0-9]{3,4}$"     # 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++ 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) numberbool 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 Codeint 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
true
true
false
false
avanitrachhadiya2155
yuvraj_chandra
kashishsoda
CPP-regex
java-regular-expression
regular-expression
Pattern Searching
Strings
Strings
Pattern Searching
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.