CODEWITHSUNDEEP
javaarrays
Cindy
Cindy

Reputation: 93

Value only returns 0

I'm a new student at programming and my college is teaching Java.

I was doing this exercise from my homework, and can't figure out why it only returns 0.

I've been looking at the internet for the past couple of days before I decided to post here. I read somewhere that Java never changes the value 0 if I start the variable with it (i7 = 0), but even when I change to i7 = 1, it returns 0 and the array is no more of 8 indexes, but 7. Also, wasn't it supposed to start filling the array at the moment I input numbers with the keyboard? Maybe I misunderstood something? How can I make it show the smallest number?

Thanks!

//Read and array of 8 indexes and find the smallest number

I have:

    int array1[] = new int[8];
    int i7;
    int smallest = array1[0];

    System.out.println("Type 8 numbers.");

    for (i7 = 0; i7 < array1.length; i7++)
    {
       array1[i7] = keyboard.nextInt();

       if (array1[i7] < array1[0])
       {
           smallest = array1[i7];
       }
    }
    System.out.println("The smallest number is " + smallest);

Upvotes: 2

Views: 343

Answers (4)

Colin D
Colin D

Reputation: 5661

Below I have annotated your code with the location of problems or their cause:

int array1[] = new int[8];  // create an array of 8 ints. all are initially 0.
int i7;
int smallest = array1[0]; // set smallest to 0.

System.out.println("Type 8 numbers.");

for (i7 = 0; i7 < array1.length; i7++)
{
   array1[i7] = keyboard.nextInt(); // potential problem, what is 'keyboard'?

   if (array1[i7] < array1[0]) // compare last read against first read
   {
       smallest = array1[i7];
   }
}
System.out.println("The smallest number is " + smallest);

Now, here is what I would do to fix it:

int array1[] = new int[8];  // create an array of 8 ints. all are initially 0.
int i7;
int smallest = Integer.MAX_VALUE;  // set the smallest to (2^31)-1; the largest int.

System.out.println("Type 8 numbers.");

for (i7 = 0; i7 < array1.length; i7++)
{
   array1[i7] = keyboard.nextInt();

   if (array1[i7] < smallest) // compare last read against current smallest
   {
       smallest = array1[i7];
   }
}
System.out.println("The smallest number is " + smallest);

Another potential source or problems is your call to keyboard.nextInt(). What class of object is keyboard? It could be returning 0 at each call. If you run the fixed code without supplying 0 as one of the inputs and still get 0 as the smallest, then you know that your keyboard.nextInt() call has problems.

Upvotes: 1

user93353
user93353

Reputation: 14039

You initialize smallest to array1[0] which is still not initialized from user input - i.e. it starts with 0.

Now, to fix the above issue, you compare with array[0] instead of smallest in the if - but this isn't the right fix.

int array1[] = new int[8];
int i7;
System.out.println("Type 8 numbers.");
array1[0] = keyboard.nextInt();

int smallest = array1[0]

for (i7 = 1; i7 < array1.length; i7++)
{
   array1[i7] = keyboard.nextInt();

   if (array1[i7] < smallest)
   {
       smallest = array1[i7];
   }
}
System.out.println("The smallest number is " + smallest);

Alternate solution.

int array1[] = new int[8];
int i7;
int smallest;

System.out.println("Type 8 numbers.");

for (i7 = 0; i7 < array1.length; i7++)
{
   array1[i7] = keyboard.nextInt();

   if(i7 == 0)
   {
        smallest = array1[0];
   }
   else
   {
       if (array1[i7] < smallest)
       {
           smallest = array1[i7];
       }

   }
}
System.out.println("The smallest number is " + smallest);

I prefer the 1st one, though.

Upvotes: 2

RuntimeError
RuntimeError

Reputation: 105

You didn't actually asked the user for the numbers did you?

Try adding this before your for call:

Scanner sc = new Scanner(System.in);

for(int z=0;z < 8;z++){
    array1[z] = new Integer(sc.nextLine()).intValue();
}

Upvotes: 0

Zim-Zam O&#39;Pootertoot
Zim-Zam O&#39;Pootertoot

Reputation: 18148

array1[i7] < array1[0] always performs the exact same comparison; you want array1[i7] < smallest

In addition, array1[0] equals zero after it's initialized, so smallest will always equal 0 unless you're entering negative numbers. Instead, initialize smallest = Integer.MAX_VALUE. This will initialize smallest to the largest possible integer, so any numbers you enter will (probably) be smaller.

Upvotes: 0

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