Introduction
As the name suggests, menu-driven programming refers to writing programs where the program first interacts with the user, and henceforth, the user is offered a fixed number of choices to control the flow of the program.
A menu-driven program takes user input by presenting a list of options, known as the menu, from which the user can select one. These choices are offered to the user, and based on the selection the user makes, the program has different statements that get executed.
Typical systems that process menu-driven programs include washing machines with microprocessors and automated teller machines (ATMs).
Menu-driven programs in Java refer to the programs where the program will run on set cases using a switch or, if else, based on the input provided by the user.
In Java Menu driven programs allow the user to interact with the program using a Menu and various Sub menus. These programs are designed to make the user experience more intuitive and user-friendly by presenting the user with a set of options to choose from rather than requiring them to input specific commands or functions.
These types of programs offer a list of input choices to the user in the form of a menu, and then, based on the input, the program gets executed.
Calculator Example
In the below example, we provide five choices of operations, addition, subtraction, multiplication, division, and exit the program.
Here the user is confined to these choices, and this is displayed to him as a menu where the choice then executes the program accordingly using the switch statements where we define the code blocks for each of the cases.
Java Code Implementation
import java.util.Scanner;
public class Calculator {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int choice;
double num1, num2, result;
// display menu and get user's choice
do {
System.out.println("Menu:");
System.out.println("1. Addition");
System.out.println("2. Subtraction");
System.out.println("3. Multiplication");
System.out.println("4. Division");
System.out.println("5. Exit");
System.out.print("Enter your choice: ");
choice = scanner.nextInt();
//Execute the selected operation
switch (choice) {
case 1:
// addition
System.out.print("Enter first number: ");
num1 = scanner.nextDouble();
System.out.print("Enter second number: ");
num2 = scanner.nextDouble();
result = num1 + num2;
System.out.println("Result: " + result);
break;
case 2:
// subtraction
System.out.print("Enter first number: ");
num1 = scanner.nextDouble();
System.out.print("Enter second number: ");
num2 = scanner.nextDouble();
result = num1 - num2;
System.out.println("Result: " + result);
break;
case 3:
// multiplication
System.out.print("Enter first number: ");
num1 = scanner.nextDouble();
System.out.print("Enter second number: ");
num2 = scanner.nextDouble();
result = num1 * num2;
System.out.println("Result: " + result);
break;
case 4:
// division
System.out.print("Enter first number: ");
num1 = scanner.nextDouble();
System.out.print("Enter second number: ");
num2 = scanner.nextDouble();
if (num2 == 0) {
// divide-by-zero error
System.out.println("Cannot divide by zero");
} else {
result = num1 / num2;
System.out.println("Result: " + result);
}
break;
case 5:
//Exit the program
System.out.println("Exiting program...");
break;
default:
// invalid choice
System.out.println("Invalid choice, please try again.");
break;
}
} while (choice != 5); // repeat until the user chooses to exit
scanner.close(); // close the scanner
}
}Output
Bank Transaction Example
In the above example, we display a menu to the user and give him four choices. The choices are to Check the Balance, Withdrawal, deposit, and exit the program.
- Based on the choice of the user, we then write cases in our switch block.
- In check balance, we return the balance.
- In withdrawal, we reduce it by the user input; in deposit, we add the amount entered by the user, which we take as input into the old balance and display the new balance.
Code in Java
import java.util.Scanner;
public class BankTransaction {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int choice;
double balance = 0;
// display menu and get user's choice
do {
System.out.println("Menu:");
System.out.println("1. Check Balance");
System.out.println("2. Deposit");
System.out.println("3. Withdraw");
System.out.println("4. Exit");
System.out.print("Enter your choice: ");
choice = scanner.nextInt();
//Execute the selected operation
switch (choice) {
case 1:
// check balance
System.out.println("Balance: " + balance);
break;
case 2:
// deposit
System.out.print("Enter amount to deposit: ");
double deposit = scanner.nextDouble();
balance += deposit;
System.out.println("New Balance: " + balance);
break;
case 3:
// withdraw
System.out.print("Enter amount to withdraw: ");
double withdraw = scanner.nextDouble();
if (withdraw > balance) {
//Insufficient balance
System.out.println("Insufficient balance");
} else {
balance -= withdraw;
System.out.println("New Balance: " + balance);
}
break;
case 4:
//Exit the program
System.out.println("Exiting program...");
break;
default:
// invalid choice
System.out.println("Invalid choice, please try again.");
break;
}
} while (choice != 4); // repeat until the user chooses to exit
scanner.close(); // close the scanner
}
}
Output
Uses of Menu-Driven Programs
Here let's discuss some real-world applications of Menu Driven Programs.
- Error reduction- Because the program executes only for some inputs that are provided to the user's GUI, the chance of getting an error is reduced considerably, as the input is already set.
- Input ambiguity is also resolved in menu-driven programs because these programs limit the number of characters that can be given as input.
- Many utilities, such as file compression programs, backup tools, and network diagnostics tools, are menu-driven. These programs allow users to perform specific functions, such as compressing files or performing a network trace.
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