Nigeria Institute Of Computing and ICT.

#### I bring to you the 3rd tutorial on Introduction to Programming using Microsoft Studio IDE tutorial 3, did you miss tutorial 1 and tutorial 2 don't worry below are the links to study it from basic introduction.

Note that at the basic introduction in Tutorial1 I solve the exercise at the end of the tutorial and its just for you to be sure of what you are doing. Lets roll.

 Operators Using Microsoft Visual Basic

#### Objectives Of This Tutorial 3 are:

• Understand what operators are in visual basic
• Gain experience with three types of operators in visual basic
• Know the rules for operator precedence and associativity

#### Introduction To Operators In Microsof Visual Basic.

An operator is a symbol used to carry out an action. A variable or a value involved in an operation is called an operand. An operator may have one or two operands. Those operators that work with only one operand are called unary operators. And those operators that work with two operands are called binary operators.

#### There are three types of operators:

• Arithmetic operators
• Relational operators
• Logical operators

#### Arithmetic Operators

Arithmetic operators are operators used in calculations. The following is a table of arithmetic operators.

 Operator Symbol Addition + Subtraction - Multiplication * Division (floating point) / Division (integer) \ Modulus Mod Exponentiation ^ Unary minus - Unary plus +

Write a program (ArithmeticOpTest) that receives two numbers from the user and then output results for each arithmetic operator applied on the two numbers.

#### Relational (Comparison) Operators

Relational operators are used to compare values. The result of the comparison is always Boolean (true or false). Relational operators are summarized in the following table:

 Operator Symbol Equal to = Not equal to <> Less than < Less than or equal to <= Greater than > Greater than or equal to >=

Write a program (RelationalOpTest) that receives two numbers from the user and then output results for each relational operator applied on the two numbers.

#### Logical Operators

Unlike relational expressions which are used to compare values, logical operators are used to compare Boolean expressions. Logical operators work base on Truth tables. The result of the comparison is always Boolean. Logical operators are summarized in the following table:
 Logical Operators And Or AndAlso OrElse Xor Not

Questions:
• What is the difference between And and AndAlso logical operators?
• What is the difference between Or and OrElse logical operators?
Given that:

Dim gender as Char = “F”
Dim grade as Double = 57.5
Dim age as Byte = 70
What is the result of the following expressions?

 gender=”F” And age>=65 grade >39 And grade <70 Not (gender=”M”) gender = “M” Xor gender = “F”

#### Operator Precedence and Associativity

Solve this equation:

When several operations occur in an expression, each part is evaluated and resolved in a predetermined order called operator precedence.
When operators of equal precedence appear together in an expression, the operators are evaluated from left to right. This is called associativity.
Summary of Operator Precedence

 Rank Operator 1 ( ) 2 ^ 3 + - (unary) 4 * / 5 \ 6 Mod 7 + - (binary) 8 & 9 < <= > >= = <> 10 Not 11 And AndAlso 12 Or OrElse 13 Xor 14 = += -= *= /= \= ^= &=

Rewrite each of the following mathematical expression in their visual basic form:

 Mathematical expression Visual Basic equivalent

Exercise:
1. Write a program (threenums) that inputs three integers from the user and displays the sum, average and product of the numbers.
1. Write a program (circle) that inputs from the user, the radius of a circle and prints the diameter, circumference and area. Use 3.14159 as the value for Ï€.
Remember:

1. The area of a triangle is given by . Write a program (triangle) that prompts a user for the values of the base and height of a triangle. The program should use these values to calculate and output the area of the triangle to the console.