MSWLogo - Text Commands and Arithmetic Operations | Year 4 Computing IGCSE (Cambridge) PDF Download

Using Text Commands to Display Text on the Screen

In MSWLogo, you can display text on the screen using the PRINT command. This command allows you to show messages, results, or instructions to the user. It is useful for communicating information or debugging your code.

Syntax:

The basic syntax to display text is:

• PRINT "text"

For example, to display the message "Hello, World!" on the screen, you would use the following command:

• PRINT "Hello, World!"

This command will display the text inside the quotation marks on the screen. You can also use the SHOW command to display text in the MSWLogo console, but PRINT is generally used for visual output on the screen.

Understanding the Use of Variables in MSWLogo

In MSWLogo, variables are used to store information that can be used later in the program. Variables are helpful when you need to store values that might change or that you need to reference multiple times. For example, you can store a number in a variable and use it to perform calculations or control movement.

Declaring Variables:

To declare a variable in MSWLogo, use the MAKE command. The syntax is:

• MAKE variable-name value

For example, to create a variable called x and assign it the value 10, you would use:

• MAKE "x 10

Using Variables:

Once a variable is defined, you can use it in your program. To refer to the value of a variable, use the variable name with a quotation mark. For example, to display the value of x on the screen, you would use:

• PRINT "x

MSWLogo will print the value stored in the variable x (in this case, 10) on the screen.

Performing Arithmetic Operations (Addition, Subtraction, Multiplication, Division)

MSWLogo allows you to perform basic arithmetic operations like addition, subtraction, multiplication, and division using simple commands. These operations can be used in conjunction with variables and other commands to solve problems and create complex programs.

Arithmetic Operations:

• Addition (+): The plus sign (+) is used to add two numbers together.
• Subtraction (-): The minus sign (-) is used to subtract one number from another.
• Multiplication (*): The asterisk (*) is used to multiply two numbers.
• Division (/): The forward slash (/) is used to divide one number by another.

Examples:

• 5 + 3 will result in 8 (addition).
• 10 - 4 will result in 6 (subtraction).
• 6 * 7 will result in 42 (multiplication).
• 20 / 4 will result in 5 (division).

Using Arithmetic Operations with Variables:

You can also use arithmetic operations with variables. For example:

• MAKE "a 10 (sets variable a to 10)
• MAKE "b 5 (sets variable b to 5)
• PRINT :a + :b (this will display the sum of a and b, which is 15)

Order of Operations:

Just like in regular mathematics, MSWLogo follows the order of operations when performing arithmetic. Operations inside parentheses are done first, followed by multiplication and division, and then addition and subtraction.

Using the MSWLogo Language for Problem-Solving

MSWLogo is a powerful tool for solving problems using programming. By combining text commands, variables, and arithmetic operations, you can solve complex problems and create useful programs.

Example: Calculating the Area of a Rectangle

Let’s say we want to calculate the area of a rectangle with a length of 10 units and a width of 5 units. The formula for the area of a rectangle is:

• Area = Length * Width

In MSWLogo, we can write the following program:

• MAKE "length 10 (sets the length variable to 10)
• MAKE "width 5 (sets the width variable to 5)
• MAKE "area :length * :width (calculates the area)
• PRINT "area (displays the area, which is 50)

This simple program uses variables to store the length and width, then calculates the area by multiplying them together. Finally, it prints the result on the screen.

Summary:

In this chapter, we learned how to use MSWLogo to display text on the screen, create and use variables, and perform arithmetic operations like addition, subtraction, multiplication, and division. We also explored how to solve problems using MSWLogo by writing simple programs that use text commands and arithmetic operations. MSWLogo is a great way to learn programming and problem-solving while creating interesting and useful programs.