For Loop - Integers stuck @ "0"

[Jordan Grimes]

I have this code running correctly in Eclipse all except that it seems no matter where I declare, highest, lowest, average they always seem to stay at "0".

I have a feeling the location of the Initialization is not the error since I have tried moving it to inside differ loops.

Stipulations on writing this code are:
Note: You do not need to use array to save each input score for this lab. A Single loop to read in each grade, compare with the current highest grade, lowest grade, and
calculate the running sum at the same time.

Yes this is homework and I have dug all through my book and the web trying to figure out where I messed up.

import java.util.Scanner;

/*Write a program that prompts the user to enter the total number of students first. 
 *Then ask the user to input each student’s grade and use loop statements to read in each grade. 
 *Check input grade to make sure 0<=grade<=100, if the user input any other number, print out 
 *warning message and ask the user to input a new grade. Display the highest score, 
 *the lowest score and the average.
 */

public class LoopStatements {
	// Main Method
	public static void main(String[] args) {
		// Initialize
		int grade = 0; 				// grade value
		int numberofstudents = 0;	// total number of students to be inputed
		int numberofgrades = 0;		// number of grades for student being entered
		float total = 0; 			// sum of grades
		
		// Create Scanner
		Scanner input = new Scanner(System.in);

		// Prompt user to input total number of Students.
		System.out.println("Please enter the total number of Students: ");
		numberofstudents = input.nextInt();
		
		//Set loop continuation to run for numberofstudents being entered.
		for (int i = 0; i < numberofstudents; i++) {
			// Prompt user to enter student grades. 
			System.out.println("Please enter number of grades for Student: ");
			numberofgrades = input.nextInt();
						
			//Set loop continuation to run for numberofgrades to be entered for that student.
			for (int j=0; j < numberofgrades; j++) {
				//Prompt user to enter a grade.
				System.out.println("Please enter Students' grade:");
				grade = input.nextInt();
				
				//Initialize 
				int highest = 0; 			// running highest grade
				int lowest = 0; 			// running lowest grade
				double average = 0; 		// average of grades
				
				//Test to see if grade is valid
				while (grade < 0 || grade > 100) {
					System.out.println("Grade must be between 0 and 100.\nPlease enter another grade\n");
					
					//Determine if this is highest grade so far and store for highest
					if (grade > highest) {
						highest = grade;
					}
					
					//Determine if this is lowest grade so far and store for lowest
					if (grade < lowest) {
						lowest = grade;
					}
					total += grade;
			
				average = (total/numberofgrades);
				
				}
				System.out.println("The highest grade is " + highest);
				System.out.println("The lowest grade is " + lowest);
				System.out.println("The average grade is " + average);
			}
		}	
	}	
}

[Rico Felix]

What is the following checking for?

while (grade < 0 || grade > 100)

[Jordan Grimes]

That is checking to make sure the grade entered is between 0and100. But now that you mention it...that creates an infinite loop. I just entered 101 and I get an infinite loop of the println ().

[Rico Felix]

Exactly...

And besides, it doesn't perform what is required because it never prompts the user for input...

[Jordan Grimes]

Ok, i believe I have fixed the Grade Checking issue...and my integers are now display numbers but the while loop runs indefinitely.

import java.util.Scanner;

/*Write a program that prompts the user to enter the total number of students first. 
 *Then ask the user to input each student’s grade and use loop statements to read in each grade. 
 *Check input grade to make sure 0<=grade<=100, if the user input any other number, print out 
 *warning message and ask the user to input a new grade. Display the highest score, 
 *the lowest score and the average.
 */

public class LoopStatements {
	// Main Method
	public static void main(String[] args) {
		// Initialize
		int grade = 0; 				// grade value
		int numberofstudents = 0;	// total number of students to be inputed
		int numberofgrades = 0;		// number of grades for student being entered
		float total = 0; 			// sum of grades
		
		// Create Scanner
		Scanner input = new Scanner(System.in);

		// Prompt user to input total number of Students.
		System.out.println("Please enter the total number of Students: ");
		numberofstudents = input.nextInt();
		
		//Set loop continuation to run for numberofstudents being entered.
		for (int i = 0; i < numberofstudents; i++) {
			// Prompt user to enter student grades. 
			System.out.println("Please enter number of grades for Student: ");
		//Set loop continuation to run for numberofgrades to be entered for that student.
			for (int j=0; j < numberofgrades; j++) {
				//Prompt user to enter a grade.
				System.out.println("Please enter Students' grade:");
				grade = input.nextInt();
				
				
				//Test to see if grade is valid
				if (grade < 0 || grade > 100) {
					System.out.println("Grade must be between 0 and 100.\nPlease enter another grade\n");
				}
			
				while (grade >= 0 && grade <= 100) {
					
					//Initialize 
					int highest = 0; 			// running highest grade
					int lowest = 0; 			// running lowest grade
					double average = 0; 		// average of grades
					
					//Determine if this is highest grade so far and store for highest
					if (grade > highest) {
						highest = grade;
					}
					
					//Determine if this is lowest grade so far and store for lowest
					if (grade < lowest) {
						lowest = grade;
					}
					total += grade;
			
				average = (total/numberofgrades);
				
				System.out.println("The highest grade is " + highest);
				System.out.println("The lowest grade is " + lowest);
				System.out.println("The average grade is " + average);
				}
			}
			
		}
	}	
}

[Rico Felix]

Before I leave the Ranch for the night I will leave you with this hint -> The scope in which you declare variables determine their values upon entering the scope and exiting...

[Jordan Grimes]

Ok thanks. That makes since. Think I got it now.

[Rico Felix]

Also you must think about what you are trying to do in terms you understand before translating it to code [English]...

For your range checking problem you are saying -> while the value entered is not in range, get another value

Which translates to:

while (grade < 0 || grade > 100)
{
  System.out.println("Grade must be between 0 and 100.\nPlease enter another grade\n");
  grade = input.nextInt();
}