Chris - 1 year ago 56

Java Question

I'm trying to create a random sum generator that generators random sums!

The only problem with what I created is, it can generate sums that have a negative result as well. So I want it to only generate sums with positive outcomes.

Example:

`7-10 = -3`

My code:

`number1 = (int)(Math.random()* LT) + 1;`

number2 = (int)(Math.random()* LT) + 1;

operator = (int)(Math.random()* OP) + 1;

switch(operator) {

case 1:

operation = "+";

result = number1 + number2;

break;

case 2:

operation = "-";

result = number1 - number2;

break;

case 3:

operation = "*";

result = number1 * number2;

break;

case 4:

operation = "/";

result = number1 * number2;

break;

}

Answer Source

Since you will always be dealing with positive integers your only issue is checking for negative numbers in your subtraction case. I would also recommend switching to the `Random`

class to generate random integers. One way to get around negative results is to flip the numbers you are subtracting.

```
boolean flip = false;
int num1, num2, op, result;
String operation;
Random r = new Random();
num1 = r.nextInt(8)+2;
num2 = r.nextInt(8)+2;
op = r.nextInt(4);
switch(op) {
case 0:
// Always be positive.
operation = "+";
result = num1+num2
break;
case 1:
// Could be negative if num2 is larger than num1. Simply flip the numbers.
flip = num1 < num2;
operation = "-";
result = flip ? num2-num1 : num1-num2;
break;
case 2:
// Always be positive.
operation = "*";
result = num1*num2;
break;
case 3:
// Always be positive.
operation = "/";
result = num1/num2;
break;
}
```