Code for finding if String contains only letters and $ character..??

Question

java
  private String normalizeDiscountCode(String discountCode){
    if( discountCode != "[a-zA-z]" || char!= '$'){
      throw new IllegalArgumentException("Invalid Discount Code");
    }

Steve Hunter · Accepted Answer

Hi Atul, 
You need to break the parameter that is passed in into a char array and iterate over each char in turn. There, test to see if the character is a letter (Use the class method isLetter()). Also test if the character is a dollar sign. It is better to test whether the character is not a letter and not a dollar sign. Use the not operator, !.
So, set up a for loop and break the discountCode (or whatever you called your parameter) down to an array using toCharArray(). Then do the test, !Character.isLetter(c) where c is your loop local variable && also c != '$'. If that evaluates to true, throw the IllegalArgumentException, else return the upper case discountCode and exit the method. That all looks like: 
java
  private String normalizeDiscountCode(String code){
    for(char c : code.toCharArray()){
      if(!Character.isLetter(c) && c != '$'){
        throw new IllegalArgumentException("Invalid discount code.");
      }
    }
    return code.toUpperCase();
  }

This post (https://teamtreehouse.com/community/can-i-get-help-for-this-problem-i-am-not-able-to-solve-it-what-is-wrong-in-the-code-which-i-wrote-in-the-program) Goes into a little more detail of this, should you need it. 
Steve.

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Atul Varma

Atul Varma

Code for finding if String contains only letters and $ character..??

1 Answer

Steve Hunter

Steve Hunter