Need help determining maximum and minimum of user inputs

user_8604984 0
Viewed 71

I am trying to determine if each input a user provides is the max or min out of all of their inputs, and then assign that input to a variable high or low

int inputnum = 0;
    double sum = 0;
    double lastinput = 0;
    double high;
    double low;
    double average;
    Scanner input = new Scanner(System.in);
    high = 0;
    low = 0;
do {
    System.out.println("Enter a number. Type 0 to quit.");
    lastinput = input.nextDouble(); //reads input
    sum += lastinput; //add to sum
    if (lastinput != 0) {
        inputnum += 1; //counts number of inputs (except 0)
    }
    if (lastinput > high && lastinput != 0) {
        high = lastinput;
    }
    if (lastinput < low && lastinput != 0) {
        low = lastinput;
    }

    average = (sum / inputnum);

} while (lastinput !=0); //repeat unless user inputs 0

The problem is that I cannot declare the variable without assigning it a value (for example 0). If a user inputs 3, 5, and 7 for example, the low value is still defined as 0.

max min java
4 Answers

That's because you intialize low to zero, and all the values you enter are bigger, so it will never be updated. You have to assign it to the highest possible value - low = Double.MAX_VALUE; so all the other values will be lower than it.

Similarly, you should initialize high as

high = Double.MIN_VALUE;
user_34263280

The problem is with your following condition:

if (lastinput < low && lastinput != 0) {
    low = lastinput;
}

Notice that the variable low is 0 initially. So if your actual minimum is higher than 0, then it will not affect the value of low because it is 0. There can be several logical solutions to this:

  1. Use a sentinel value : Initialise low with the highest possible value of double so that the user input is always lower, therefore affects the value of low

    double low = Double.MAX_VALUE;

  2. Change the if condition : You could change the if condition to account for the fact that the initial value is 0.

    if (low==0 || (lastinput < low && lastinput != 0)) {
    low = lastinput;
}
user_64518020

You should use a maximum value for low by default or else the condition lastinput < low for non-negative inputs would always be false and 0 remains as your output.

double low = Double.MAX_VALUE;
user_17461180

The value of low and high can be initialed by your first input before your loop.

user_23605350
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