CODEWITHSUNDEEP
javaarrays
user4860379
user4860379

Reputation:

Basic array - Java

I need to make 2 arrays called A and B, both of type int with size 100. Each index should be a random number between 0 and 100 inclusive and then compare both arrays, and say how many times 2 of the same number appeared in both arrays.

This is what I have so far

int count = 0;

int [] A = new int [100];
int [] B = new int [100];

for(int i = 0; i < A.length; i++){
    A [i] = (int)(Math.random()*101);
    System.out.println("Array A: " + i);
}
for(int i = 0; i < B.length; i++){
    B [i] = (int)(Math.random()*101);
    System.out.println("Array B: " + i);
}

if(A [i] == B [i]){
    count++;
}

I'm not sure how to show how many times 2 of the same number appeared in both arrays.

Upvotes: 0

Views: 103

Answers (3)

John Schwartz
John Schwartz

Reputation: 104

You started off nicely, but you need a nested for-loop to check each of the indexes.

ALSO-- make sure that in your arrays you print out A[i] and B[i] otherwise you're just printing out the number of the index as opposed to the number inside the index.

  int count = 0;

  int[] A = new int[100];
  int[] B = new int[100];      

  //Create the first array
  for (int i = 0; i < A.length; i++) {
     A[i] = (int)(Math.random() * 101);
     System.out.println("Array A: " + A[i]);
  }

  //Create the second array
  for (int i = 0; i < B.length; i++) {
     B[i] = (int)(Math.random() * 101);
     System.out.println("Array B: " + B[i]);
  }

  //Check the indexes and make sure they are all compared-- 10,000 comparisons are made
  for (int i = 0; i < A.length; i++) {    
     for (int j = 0; j < B.length; j++) {
        if(A[i] == B[j])
           count++;
     }
  }

Hopefully that posted correctly... first time posting code on this website, but I hope that I was of help!

Keep in mind if the same number is being posted twice, you're going to get counts over 100.

Good luck!

Upvotes: 0

Jean Logeart
Jean Logeart

Reputation: 53829

Alternatively, if you don't need the 2 arrays, you can simply do:

int count = Random.ints(100, 0, 101).boxed().collect(toSet())
                  .retainAll(Random.ints(100, 0, 101).boxed().collect(toSet()))
                  .size();

Upvotes: 1

Mohammed Aouf Zouag
Mohammed Aouf Zouag

Reputation: 17132

You need to loop through both of the arrays:

int count = 0;

int [] A = new int [100];
int [] B = new int [100];

for(int i = 0; i < A.length; i++){
    A [i] = (int)(Math.random()*101);
    System.out.println("Array A: " + i);
}
for(int i = 0; i < B.length; i++){
    B [i] = (int)(Math.random()*101);
    System.out.println("Array B: " + i);
}

// Loop through the first array
for(int i = 0; i < A.length; i++) {
    // For each element in the first array, loop through the whole second one
    for (int j = 0; j < B.length; j++) {
        // If it's a match
        if(A[i] == B[j])
            count++;
    }
}

System.out.println("Count: " + count);

Upvotes: 1

Related Questions