Use value outside for loop

Question

public class randomdemo {
    public static void main(String[] args)
    {
        Random rand = new Random();
        int [] varArray = new int[rand.nextInt(10)];

        System.out.println(varArray.length);
        int d = rand.nextInt(1999)-1000;
        for (int i=0;i<varArray.length;i++)
        {
            varArray[i]= rand.nextInt(1999)-1000;
            System.out.println(varArray[i]);

            if(d==varArray[i])
            {
                System.out.println(d);      
                System.out.println(i+1);
            }
            else
            { 
                System.out.println(d);
                System.out.println(0);
            }
        }
    }
}

Problems in code:

It executes the if-else statement multiple times and displays the if-else output multiple times since it is in for loop. The code should execute the if-else statement only once but the rest of the for loop should be executed multiple times. Since the if statement is using value of varArray[i] I cannot exclude the code from the for loop. When break statement is used it is terminating the for loop. and the complete output is not shown.

output: currently

7 -710 -249 0 -693 -249 0 172 -249 0 -488 -249 0 -48 -249 0 955 -249 0 869 -249 0

As you can see the length of array is 7 it displays array element then value of variable d and value 0 in a loop.

expected output:

7 -710 -693 172 -488 -48 955 869 -249 0

the output of array with 7 elements should be 7 array values followed by variable d and 0.

Answer 1

Please identify the exact scenario in which you want to execute the if-else and make changes in the existing if-else condition so that it executes only once in the loop. Or you can wrap the existing if-else inside other if-else,for which the condition can be the scenario in which you have to execute the inner if-else.

For eg: Let the scenario is like only for a particular value of i(say when i=10) you want to execute the loop.Please modify the code as below.

if(i==10){
 if(d==varArray[i])
            {
                System.out.println(d);      
                System.out.println(i+1);
            }
            else
            { 
                System.out.println(d);
                System.out.println(0);
            }

}

Answer 2

May be you can set a boolean flag to track execution of your if else code .. see code below.

    boolean flag = false;  // flag to track the if else

    System.out.println(varArray.length);
    int d = rand.nextInt(1999)-1000;
    for (int i=0;i<varArray.length;i++)
    { 
      ...
       if(!flag){
        if(d==varArray[i])
        {
            flag =true;
            System.out.println(d);      
            System.out.println(i+1);
        }
        else
        { 
             flag =true;
            System.out.println(d);
            System.out.println(0);
        }
       }

Answer 3

Try this.

public class randomdemo {

    public static void main(String[] args) {
        Random rand = new Random();
        int[] varArray = new int[rand.nextInt(10)];

        System.out.println(varArray.length);
        int d = rand.nextInt(1999) - 1000;
        int foundIdx = -1; // mark index if you find one!
        for (int i = 0; i < varArray.length; i++) {
            varArray[i] = rand.nextInt(1999) - 1000;
            System.out.println(varArray[i]);

            if (d == varArray[i]) {
                foundIdx = i + 1; // only the last match is saved
            }
        }
        if (foundIdx != -1) {
            System.out.println(d);
            System.out.println(foundIdx);
        } else {
            System.out.println(d);
            System.out.println(0);
        }
    }
}