I need to program a lottery simulator and basically everything works fine but I have one small problem at the end of the problem. There are 2 Arrays(i need to work without Array Lists) which get compared. The generated winning numbers and the numbers entered by the user. I succeeded in showing what numbers are the right guesses. But what doesn't work is showing HOW MANY guesses were correct. I tried System.out.println("You guessed this many numbers right: " intArray.length[i] but this didn't work. Is there any way to show the exact number of how many numbers were guessed right? Thanks for any help in advance

  for (int i=0; i< intArray.length;i  ){

        for (int j=0; j< ownArray.length;j  ){

            if (intArray[i] == ownArray[j]){




                System.out.println("Your following guess was correct: " intArray[i]);

CodePudding user response：

Just use a count variable

public static void main(String[] args) {
    int[] intArray = {1,2,4,5};
    int[] ownArray = {1,0,2,7};
    int count = 0;
    System.out.println("Your following guesses were correct: ");
    for (int i = 0; i < intArray.length; i  ){
        for (int j = 0; j < ownArray.length; j  ){
            if (intArray[i] == ownArray[j]){
                System.out.print(intArray[i]   " ");
                count  ;
            }
        }
    }
    System.out.println("\nNo. of correct guesses: "   count);
}

Output: Your following guesses were correct: 1 2 No. of correct guesses: 2

CodePudding user response：

This is actually quite simple to do if your lottery numbers are positive numbers. It is more involved if the numbers can be negative. The basic algorithm is to compare lottery numbers one by one against all the player's guesses repeatedly. If there is a match then we record -1 in the user guess array and increment a counter to track the number of correct entries.

Some code will make this clearer:

public class LotteryNumbers {


    public static void main(String[] args) {
        int[] lotteryNumbers = {1,2,3,4,5,6};
        int[] userGuess = {1,2,3,4,8,9};
        int correct = 0;

        for(int i=0; i<lotteryNumbers.length; i  ) {
            for(int j=0; j<userGuess.length; j  ) {
                if( userGuess[j] == lotteryNumbers[i]) {
                    userGuess[j] = -1; // 'eliminate' this guess for checking
                    correct  ;
                    break;
                }
            }
        }

        System.out.println("Number of correct numbers = "   correct);
    }
}

Outputs:

Number of correct numbers = 4

This works because the algorithm strikes out matches in the player's guesses and guards against future matching next time through the loop. You can imagine that what we are actually doing is striking off numbers in the player's guess that match against the lottery numbers.