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f7e663a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 | Write a program that asks the user to enter integers.
The program adds the numbers entered by the user to the list in the order in which they were entered.
When the user enters -1, the program terminates and prints the list.
If the user's input contains anything other than numbers, the program ignores the input.
Example execution:
Give a number: 2
Give a number: 3
Give a number: sdf
Give a number: 4
Give a number: 5
Give a number: forty
Give a number: -1
[2, 3, 4, 5]
import java.util.Random;
import java.util.ArrayList;
import java.util.Scanner;
public class Test{
public static void main(String[] args){
final Random r = new Random();
ArrayList<Integer> list = new ArrayList<>();
// DONT RECREATE SCANNER EVERY ITERATION
Scanner reader = new Scanner(System.in);
while (true) {
try {
System.out.print("Give a number: ");
int user_num = Integer.valueOf(reader.nextLine());
// terminate if user enters '-1'
if (user_num == -1) {
break;
}
else {
list.add(user_num);
}
}
// ignore error and continue if user enters non-integer
catch (Exception e) {
continue;
}
}
System.out.println(list);
}
}
Test number 1
Give a number: 2
Give a number: 3
Give a number: 4
Give a number: x
Give a number: 5
Give a number: -1
[2, 3, 4, 5]
Test number 2
Give a number: six
Give a number: 10
Give a number: 12
Give a number: asdads
Give a number: 14
Give a number: 16q
Give a number: we
Give a number: -1
[10, 12, 14]
Test number 3
Give a number: 9
Give a number: 9
Give a number: nine
Give a number: nine
Give a number: 9
Give a number: 9
Give a number: 8
Give a number: 7
Give a number: too
Give a number: 2
Give a number: f2
Give a number: -1
[9, 9, 9, 9, 8, 7, 2]
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