SunnyX
asked on
core java. isInteger methods. Finding bug.
public static int isInputInteger(){
@SuppressWarnings("resource")
Scanner input = new Scanner(System.in);
int correctNumber;
while(true){
input.nextLine();
if(input.hasNextInt()){
correctNumber = input.nextInt();
break;
}
else{
System.out.println("Your input isn't integer.Please, try again. ");
}
}
return correctNumber;
}class PrintFromInput {
protected static int printNumber() {
System.out.printf("Please, enter integer: ");
int intYourConsoleInput = Assert.isInputInteger();
return intYourConsoleInput;
}
}
public class Task {
public static void main(String[] args) {
System.out.println("Congratulation! Your correct integer input is: "+ PrintFromInput.printNumber());
}
}Inside class Assert there is a method "isInputInteger" everything work but not as I expect :
Session 1
input : f
output: {nothing }
input : f
output : Your input isn't integer.Please, try again.
input: g
output : Your input isn't integer.Please, try again.
input : 3
Congratulation! Your correct integer input is: 3
Session OVER
My question is why there isn't any message after first "f". Please, help me to find bug. Thx in advance !
krakatoa
At first glance, maybe because you are advancing the scanner too early.
why don'y you try setting breakpoints and debugging to find out what going on?
Remove this line :
input.nextLine();SOLUTION
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Yes, indeed. I thought the OP would be able to work out the required code move once he sees the result of just deleting it.
SOLUTION
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ASKER CERTIFIED SOLUTION
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ASKER
The solution is :
Dear experts thx you so much for your help !
public static int onlyIntegerInput(){
@SuppressWarnings("resource")
Scanner scanner = new Scanner(System.in);
int correctNumber;
while (true){
if(!(scanner.hasNextInt())){
System.out.println("Your input isn't integer. Please, try again. ");
scanner.next();
continue;
}
else{
correctNumber = scanner.nextInt();
break;
}
}
return correctNumber;
}Dear experts thx you so much for your help !
ASKER
Everybody many thanks !
Yes, that's it.