Multi tool use

How to declare unlimited variables in a loop depending on user input?

I am building a program in eclipse and I want to make a loop in which variables are declared depending on user input.
for eg, the first input is stored in a1, next input in a2, next one in a3, and so on until the user types anything other than a number input.hasNextDouble().

input.hasNextDouble()

I tried doing this using while loop, and Scanner class with if/else statements. But unable to figure it out. Any help will be appreciated.

while

Scanner

if/else

List

List

1 Answer
1

You could use a HashMap:

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

class Main {
public static void main(String args) {
Scanner scanner = new Scanner(System.in);

Map<String, Double> inputs = new HashMap<String, Double>();

boolean isNumber = true;
int count = 1;
while(isNumber) {
System.out.printf("Please enter a%d:", count);
if(scanner.hasNextDouble()) {
inputs.put("a" + count, scanner.nextDouble());
count++;
} else {
isNumber = false;
}
}

System.out.println("Inputs: " + inputs);

// Auxiallary code for question in comments below
double sum = 0.0f;
for (double d : inputs.values()) {
sum += d;
}

System.out.println("Sum: " + sum);

for (Map.Entry<String, Double> entry : inputs.entrySet()) {
System.out.println("Sum - " + entry.getKey() + " = " + (sum - entry.getValue()));
}
}
}


Example Usage:

Please enter a1: 5.5
Please enter a2: 6
Please enter a3: 7.2
Please enter a4: x
Inputs: {a1=5.5, a2=6.0, a3=7.2}
Sum: 18.7
Sum - a1 = 13.2
Sum - a2 = 12.7
Sum - a3 = 11.5


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