Java Variables and Data Types Challenge: Build a Simple Student Profile

Problem statement

A school wants a simple program that can display a student's basic profile on the screen. Your task is to create a Java program that asks the user for a student's name, age, grade average, and whether the student is currently enrolled.

The program must store each value using an appropriate data type and then display the full student profile in a clear format. If the user enters invalid data for age, grade average, or enrollment status, the program should show a clear error message.

Input and output expectations

• Input: student name as text
• Input: age as a whole number
• Input: grade average as a decimal number
• Input: enrollment status as true or false
• Output: a formatted student profile showing all entered values
• Output: an error message if age, grade average, or enrollment status is invalid

Constraints

• Do not use file input or file output
• Do not use databases or network requests
• Age must be between 1 and 120
• Grade average must be between 0 and 100
• Enrollment status must be either true or false
• Use only beginner-friendly Java concepts

Hints

• Use a String for the student's name
• Use an int for the age
• Use a double for the grade average
• Use a boolean for the enrollment status
• Validate user input before showing the final profile

Solution explanation

First, ask the user to enter the student's name and store it in a string variable. Then ask for the age and check that the input is a whole number before storing it in an integer variable.

Next, ask for the grade average and make sure it is a decimal or whole number. Store it in a double variable. After that, ask whether the student is enrolled and check that the answer is either true or false before storing it in a boolean variable.

Once all values are valid, print the student profile in a readable format. This challenge helps you practice choosing the correct data type for different kinds of information.

Solution

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter student name: ");
        String studentName = scanner.nextLine().trim();

        if (studentName.isEmpty()) {
            System.out.println("Error: Name cannot be empty.");
            return;
        }

        System.out.print("Enter age: ");
        if (!scanner.hasNextInt()) {
            System.out.println("Error: Age must be a whole number.");
            return;
        }
        int age = scanner.nextInt();

        if (age < 1 || age > 120) {
            System.out.println("Error: Age must be between 1 and 120.");
            return;
        }

        System.out.print("Enter grade average: ");
        if (!scanner.hasNextDouble()) {
            System.out.println("Error: Grade average must be a number.");
            return;
        }
        double gradeAverage = scanner.nextDouble();

        if (gradeAverage < 0 || gradeAverage > 100) {
            System.out.println("Error: Grade average must be between 0 and 100.");
            return;
        }

        System.out.print("Is the student enrolled? (true/false): ");
        if (!scanner.hasNextBoolean()) {
            System.out.println("Error: Enrollment status must be true or false.");
            return;
        }
        boolean isEnrolled = scanner.nextBoolean();

        System.out.println();
        System.out.println("Student Profile");
        System.out.println("Name: " + studentName);
        System.out.println("Age: " + age);
        System.out.printf("Grade Average: %.2f%n", gradeAverage);
        System.out.println("Enrolled: " + isEnrolled);
    }
}

/*
Sample Output:
Enter student name: Maria
Enter age: 18
Enter grade average: 89.5
Is the student enrolled? (true/false): true

Student Profile
Name: Maria
Age: 18
Grade Average: 89.50
Enrolled: true
*/

Variations or next challenges

• Add a character variable for the student's section letter
• Display whether the student passed based on the grade average
• Ask for two students and compare their grade averages
• Format the output as a small report card
• Calculate how many years remain before the student turns 21

Related snippets or guides

• Java variables
• Primitive data types
• String values
• Boolean values
• User input with Scanner
• Basic input validation
• Formatted output with printf