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Java Exercises: Get the first occurrence of an element of a given array

Java Basic: Exercise-119 with Solution

Write a Java program to get the first occurrence (Position starts from 0.) of an element of a given array.

Pictorial Presentation:

Java Exercises: Get the first occurrence of an element of a given array

Sample Solution:

Java Code:

import java.util.Scanner;
public class Main {
public static void main(String[] args) {
    int nums[] = {2, 4, 6, 7, 8};
    int target = 7;
        int lower = 0;
        int upper = nums.length - 1;
        int index = -1;
        while (lower <= upper) {
            int mid = (lower + upper) >> 1;
            if (nums[mid] == target) {
                index = mid;
            }
            if (nums[mid] >= target) {
                upper = mid - 1;
            } else {
                lower = mid + 1;
            }
        }
        System.out.print("Position of "+target +" is "+index);
    }
}

Sample Output:

Position of 7 is 3 

Flowchart:

Flowchart: Java exercises: Get the first occurrence of an element of a given array

Java Code Editor:

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Next: Write a Java program to searches a value in an m x n matrix

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Java: Tips of the Day

Execution of console commands:

Java allows you to execute console commands directly from code using a class Runtime. It is very important not to forget about exception handling.

For example, let's try to open a PDF file through a Java terminal:

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
  
public class ShellCommandExec {
  
  public static void main(String[] args) {
    String gnomeOpenCommand = "gnome-open //home//user//Documents//MyDoc.pdf";
  
    try {
      Runtime rt = Runtime.getRuntime();
      Process processObj = rt.exec(gnomeOpenCommand);
  
      InputStream stdin = processObj.getErrorStream();
      InputStreamReader isr = new InputStreamReader(stdin);
      BufferedReader br = new BufferedReader(isr);
  
      String myoutput = "";
  
      while ((myoutput=br.readLine()) != null) {
        myoutput = myoutput+"\n";
      }
      System.out.println(myoutput);
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }
}