Question

What is a single alternative decision structure?

Short answer

Answer: A single alternative decision structure, also known as an "if statement," is a programming construct that allows the program to take different actions based on whether a specified condition is true or false. In this structure, if the condition is true, the program will execute a certain block of code; otherwise, it will simply skip it. In Python, it is implemented using the "if" keyword followed by a condition and a colon, with the block of code to execute indented underneath. In Java, the "if" keyword is followed by the condition enclosed in parentheses, and the block of code to execute is enclosed in curly braces. These structures allow programs to execute certain blocks of code only when specific conditions are met.

Step-by-step solution

Introduction to Single Alternative Decision Structure

A single alternative decision structure, also known as an "if statement," is a programming construct that allows the program to take different actions based on whether a specified condition is true or false. In this structure, if the condition is true, the program will execute a certain block of code; otherwise, it will simply skip it.

Example in Pseudocode

Let's first use pseudocode to emphasize the logic of the single alternative decision structure: ``` IF (condition) THEN // Code to execute if the condition is true ENDIF ``` In this pseudocode, if the condition is evaluated as true, the instructions represented by "// Code to execute if the condition is true" will be executed. If the condition is false, the program will skip this block of code and proceed to the next line after the ENDIF statement.

Example in Python

Now let's see an example in Python programming language. Assume we want to determine if a given number is even or not. ```python number = 6 if number % 2 == 0: print("The number is even.") ``` In this example, if the given number has no remainder when divided by 2 (i.e., number % 2 == 0), the program will print "The number is even." Otherwise, the program will not do anything and simply proceed.

Example in Java

Let's take a look at a similar example in Java programming language: ```java public class Example { public static void main(String[] args) { int number = 6; if (number % 2 == 0) { System.out.println("The number is even."); } } } ``` In this example, the same logic described above for the Python example is employed. If the condition "number % 2 == 0" is true, the program will print "The number is even." Otherwise, the program will not do anything and simply proceed. These examples demonstrate how single alternative decision structures allow programs to execute certain blocks of code only when specific conditions are met.