为什么这个简单的 Java 不能循环工作？

Question

I'm trying to figure out why my test program seems to be completely skipping a public class method when being called in an instantiated object in the main method. Please see below for both the "Test" class and the "Main" class where the main method creates the object and attempts to call all three class methods.

Main class:

class Main {
  public static void main(String[] args) {
    Test test = new Test();
    test.getNumOfStudents();
    test.getGrades();
    System.out.println("The average grade is " + test.calcAvgGrade() + ".");
  }
}

Test Class:

import java.util.*;

public class Test {
  
  public int numOfStudents;
  public double averageGrade;
  public double totalGrade;
  public Scanner input = new Scanner(System.in);

  public void getNumOfStudents() {
    System.out.println("How many students are enrolled?");
    this.numOfStudents = input.nextInt();
    return;
  }

  public void getGrades() {
    for(int i = 1; i == this.numOfStudents; i++) {
      System.out.print("Enter the grade of student # " + i + ":");
      this.totalGrade = input.nextDouble() + this.totalGrade;
      System.out.println("");
    }
    return;
  }

  public double calcAvgGrade() {
    this.averageGrade = this.totalGrade / this.numOfStudents;
    return this.averageGrade;
  }

}

Answer 1

When you run your for loop, you have the condition be i==this.numOfStudents . I think you are trying to make it up to this.numOfStudents .

So to fix this you would have a less than or equal to. So you would have i<=this.numOfStudents , because right now your for loop is saying run ONLY if i==this.numOfStudents .

Answer 2

In method getGrades , the for loop should be:

   for(int i = 1; i <= this.numOfStudents; i++) {
         System.out.print("Enter the grade of student # " + i + ":");
         this.totalGrade = input.nextDouble() + this.totalGrade;
         System.out.println("");
       }

Because of i == this.numOfStudents , you're having issues.