{"id":73751,"date":"2023-12-10T14:56:29","date_gmt":"2023-12-10T12:56:29","guid":{"rendered":"https:\/\/codeacademy.bg\/uncategorized-bg\/uslovni-izrazi\/"},"modified":"2024-04-08T20:01:41","modified_gmt":"2024-04-08T17:01:41","slug":"uslovni-izrazi","status":"publish","type":"post","link":"https:\/\/codeacademy.bg\/en\/programirane\/uslovni-izrazi\/","title":{"rendered":"Programming Basics: Conditional Statements if-else and switch"},"content":{"rendered":"

Conditional expressions in programming are constructs that allow control over the execution of code. Having control and ensuring your program operates as it should is crucial. Two of the most commonly used constructs for controlling execution are the conditional expressions if-else and switch. These tools allow programmers to make decisions based on certain conditions and choose which code to execute. In this article, we will explore these constructs and learn how to use them in various situations.<\/span><\/p>\n

The if-else Construct<\/span><\/p>\n

The if-else construct in programming allows the program to check conditions and execute certain code if those conditions are met. The syntax for if-else is as follows:<\/span><\/p>\n

“`python<\/span><\/p>\n

if condition:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0# Code that executes if the condition is true<\/span><\/p>\n

else:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0# Code that executes if the condition is false<\/span><\/p>\n

“`<\/span><\/p>\n

Example:<\/span><\/p>\n

“`python<\/span><\/p>\n

age = 18<\/span><\/p>\n

if age >= 18:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“You can purchase alcohol.”)<\/span><\/p>\n

else:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“You cannot purchase alcohol.”)<\/span><\/p>\n

“`<\/span><\/p>\n

In the above example, the program checks if the age is greater than or equal to 18 years and outputs a message accordingly.<\/span><\/p>\n

Nesting if-else Constructs<\/span><\/p>\n

You can also nest if-else constructs, which means you can have other if-else constructs inside an if or else block. This is called “nesting” and allows you to perform more complex checks.<\/span><\/p>\n

Example:<\/span><\/p>\n

“`python<\/span><\/p>\n

age = 18<\/span><\/p>\n

driver_license = True<\/span><\/p>\n

if age >= 18:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0if driver_license == True:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0print(“You can drive a car.”)<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0else:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0print(“You do not have a driver’s license.”)<\/span><\/p>\n

else:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“You cannot drive a car.”)<\/span><\/p>\n

“`<\/span><\/p>\n

This example shows the nesting of if-else constructs when you need to check more than one condition.<\/span><\/p>\n

The switch (or case) Construct<\/span><\/p>\n

The switch construct is specific to some programming languages like C, C++, Java, and others. It allows the program to choose which code to execute based on the value of an expression. An example of a switch construct:<\/span><\/p>\n

“`c<\/span><\/p>\n

int day_of_the_week = 3;<\/span><\/p>\n

switch (day_of_the_week) {<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0case 1:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“Monday”);<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0break;<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0case 2:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“Tuesday”);<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0break;<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0case 3:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“Wednesday”);<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0break;<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0default:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“Invalid day”);<\/span><\/p>\n

}<\/span><\/p>\n

“`<\/span><\/p>\n

In the above example, the program chooses which code to execute based on the value of the variable day_of_the_week. The break is used to prevent the execution of subsequent cases once a match is found.<\/span><\/p>\n

In some programming languages, like Python, there isn’t a standard switch construct. Instead, if-elif-else constructs are used to achieve a similar effect.<\/span><\/p>\n

Python example with if-elif-else:<\/span><\/p>\n

“`python<\/span><\/p>\n

day = 3<\/span><\/p>\n

if day == 1:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“Monday”)<\/span><\/p>\n

elif day == 2:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“Tuesday”)<\/span><\/p>\n

elif day == 3:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“Wednesday”)<\/span><\/p>\n

else:<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0print(“The day is not valid”)<\/span><\/p>\n

“`<\/span><\/p>\n

When to Use if-else and switch?<\/span><\/p>\n

– The if-else construct is suitable when you need to check different conditions and perform different actions based on those conditions. This makes if-else very flexible and suitable for a variety of scenarios.<\/span><\/p>\n

– The switch construct is useful when you need to check one value against multiple possible values and execute corresponding code for each value. This makes the code more readable and easier to maintain when there are many options.<\/span><\/p>\n

Conditional expressions if-else and switch are convenient tools for controlling execution in programming. Understanding their essence and how to use them is key to creating programs that make decisions based on various conditions. These frequently used constructs allow the program to execute different code depending on whether a given condition is met or not. These expressions are essential for controlling the program flow and ensuring the correct logic during execution. With practice and experience, you’ll become very proficient in using these constructs and will be able to create more complex and functional programs.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Conditional expressions in programming are constructs that allow control over the execution of code. Having control and ensuring your program operates as it should is crucial. Two of the most commonly used constructs for controlling execution are the conditional expressions if-else and switch. These tools allow programmers to make decisions based on certain conditions and […]<\/p>\n","protected":false},"author":1,"featured_media":73140,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"content-type":"","footnotes":""},"categories":[97,98],"tags":[],"class_list":["post-73751","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programirane","category-programirane-za-nachinaesthi","grve-entry-item","grve-blog-item"],"_links":{"self":[{"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/posts\/73751","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/comments?post=73751"}],"version-history":[{"count":1,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/posts\/73751\/revisions"}],"predecessor-version":[{"id":73752,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/posts\/73751\/revisions\/73752"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/media\/73140"}],"wp:attachment":[{"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/media?parent=73751"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/categories?post=73751"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codeacademy.bg\/en\/wp-json\/wp\/v2\/tags?post=73751"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}