# How to validate CVV number using Regular Expression

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:

1. It should have 3 or 4 digits.
2. It should have a digit between 0-9.
3. 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 ` `#include ` `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)

Feeling lost in the world of random DSA topics, wasting time without progress? It's time for a change! Join our DSA course, where we'll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 geeks!

Previous
Next