Arguments in QBasic: Understanding How to Pass and Use Them

Introduction

Arguments are essential components of any programming language, as they allow programmers to pass data between subroutines and functions. In QBasic, you can use arguments to simplify your code, make it more readable, and even make it more efficient.

In this article, we'll explain the different types of arguments in QBasic and show you how to pass them to subroutines and functions. We'll also provide examples that demonstrate the practical applications of using arguments in QBasic.

Understanding Arguments in QBasic

What are the Arguments?

In QBasic, arguments are pieces of data that you can pass between subroutines and functions. Arguments can be any data type, including integers, floating-point numbers, strings, and user-defined types.

Arguments allow you to create subroutines and functions that can be used with different data values without having to write separate code for each value. Instead, you can write a single subroutine or function that accepts arguments and performs a specific task with them.

Syntax of Arguments in QBasic

Arguments in QBasic are used to pass values to subroutines and functions. They allow us to reuse code and make our programs more efficient. In this article, we'll explore the syntax of arguments in QBasic and how to use them in our programs.

Syntax of Arguments

Arguments are variables or expressions that are passed to a subroutine or function. They are enclosed in parentheses after the subroutine or function name. The syntax for passing arguments in QBasic is as follows:

In the above examples, "argument1", "argument2", and so on, represent the names of the arguments that are being passed to the subroutine or function. You can specify as many arguments as you need, separated by commas. If you don't need any arguments, you can simply omit them.

Types of Arguments

In QBasic, there are three types of arguments: positional arguments, default arguments, and optional arguments.

Required Arguments

Required arguments are necessary for the subroutine or function to execute correctly. They are specified in the subroutine or function declaration without any default value. If a required argument is not provided when the subroutine or function is called, an error will occur.

In the above examples, "argument1" is a required argument, and "argument2" is also a required argument.

Default Arguments: 

Default arguments are optional arguments that have a predefined value. If you don't provide a value for a default argument when calling a subroutine or function, QBasic uses the predefined value.

In the above examples, "argument1" is a required argument, and "argument2" is a default argument with a default value of 10. If "argument2" is not specified when the subroutine or function is called, it will default to 10.

Optional Arguments: 

Optional arguments are also optional, but unlike default arguments, they don't have a predefined value. Instead, you can omit them when calling a subroutine or function, and QBasic assigns a default value based on the argument's data type.

In the above examples, "argument1" is a required argument, and "argument2" is an optional argument. If "argument2" is not specified when the subroutine or function is called, it will be treated as if it was not passed at all.

Passing Arguments in QBasic

In QBasic, you can pass arguments to a subroutine or function in two ways: by value and by reference.

Passing Arguments by Value: 

When you pass an argument by value, QBasic creates a copy of the argument's value and passes it to the subroutine or function. Any changes made to the argument within the subroutine or function do not affect the original value of the argument.

Passing Arguments by Reference: 

When you pass an argument by reference, QBasic passes a reference to the argument's memory location to the subroutine or function. Any changes made to the argument within the subroutine or function affect the original value of the argument.

Some solved Examples of Arguments in QBasic

1. Program for constant values can be used for an argument.

In the above program constant value '5', and '9' are called in the module avg of 'a', and 'b' variables.

2. Program for Expression can be used as an Argument.

In the above program expression 'a*a', and 'b*b' passed from main module to sub module avg in the variables 'a', and 'b'.

3. Passing Array argument to sub procedure

In the above program, the user input 5 different numbers in an array variable n(x) and pass it to the sub-procedure. The sub procedure displays them in reverse order as output.

Conclusion

In conclusion, arguments in QBasic are an essential aspect of programming that allows us to pass values to subroutines and functions. There are three types of arguments in QBasic: required, default, and optional. Required arguments are necessary for the subroutine or function to execute correctly. Default arguments have a predetermined value that is used when the argument is not specified. Optional arguments are not required, and their values may or may not be passed to the subroutine or function. Understanding how to use arguments effectively in QBasic can help you write more efficient and versatile code.

 FAQs

1) What is a required argument in QBasic? 

Ans: A required argument in QBasic is an argument that must be provided when calling a subroutine or function. It is essential for the subroutine or function to execute correctly.

2) What is a default argument in QBasic? 

Ans: A default argument in QBasic is an argument that has a predetermined value that is used when the argument is not specified. It provides a default value for the argument.

3) What is an optional argument in QBasic? 

Ans: An optional argument in QBasic is an argument that is not required, and its value may or may not be passed to the subroutine or function.

4) How do you define a subroutine in QBasic? 

Ans: To define a subroutine in QBasic, you use the SUB keyword followed by the name of the subroutine and its parameters.

5) How do you pass arguments to a subroutine in QBasic? 

Ans: To pass arguments to a subroutine in QBasic, you simply list the arguments after the subroutine name when calling the subroutine.

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