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Start your free trialTodd Anderson
4,260 PointsHow do you convert a string to check that it consists only of letters?
In the video his methods are already using char parameters, in this example we are asked to validate a string to make sure it consists of only letters. I have tried several options and all result in incomparable types.
public class Order {
private String itemName;
private int priceInCents;
private String discountCode;
public Order(String itemName, int priceInCents) {
this.itemName = itemName;
this.priceInCents = priceInCents;
}
private String normalizeDiscountCode(String discountCode){
if (! discountCode.isLetter() || discountCode != "$"){
throw new IllegalArgumentException("Invalid discount code");}
return discountCode.toUpperCase();}
public String getItemName() {
return itemName;
}
public int getPriceInCents() {
return priceInCents;
}
public String getDiscountCode() {
return discountCode;
}
public void applyDiscountCode(String discountCode) {
this.discountCode = normalizeDiscountCode(discountCode);
}
}
public class Example {
public static void main(String[] args) {
// This is here just for example use cases.
Order order = new Order(
"Yoda PEZ Dispenser",
600);
// These are valid. They are letters and the $ character only
order.applyDiscountCode("abc");
order.getDiscountCode(); // ABC
order.applyDiscountCode("$ale");
order.getDiscountCode(); // $ALE
try {
// This will throw an exception because it contains numbers
order.applyDiscountCode("ABC123");
} catch (IllegalArgumentException iae) {
System.out.println(iae.getMessage()); // Prints "Invalid discount code"
}
try {
// This will throw as well, because it contains a symbol.
order.applyDiscountCode("w@w");
}catch (IllegalArgumentException iae) {
System.out.println(iae.getMessage()); // Prints "Invalid discount code"
}
}
}
1 Answer
Livia Galeazzi
Java Web Development Techdegree Graduate 21,083 PointsYou need to check each letter in the string to see if it's correct or not. Just loop through each character and check it. One way to do it:
private String normalizeDiscountCode(String discountCode){
for (int i = 0; i < discountCode.length(); i++) {
char c = discountCode.charAt(i);
if (!Character.isLetter(c) && c != '$') {
throw new IllegalArgumentException("Invalid discount code");
}
}
return discountCode.toUpperCase();
}