The Guide to Control Structures If, If-Else, and Switch-Case in C Programming

In the C programming language, control structures such as if, if-else, and else allow programmers to make decisions during program execution. These structures are used to branch the flow of execution based on specific conditions. In programming, control structures enable the management of program execution flow. They determine which parts of the code will be executed and under what conditions. By using if, if-else, and if-else if-else structures, programmers can write flexible programs that make decisions based on various conditions. Proper use of these control structures enables efficient management of the program execution flow and increases code readability.

if statement

The if statement is used to check a specific condition. If the condition is true, the block of code within the if statement is executed. If the condition is not true, that block of code is skipped, and the program continues. if statements can be nested, meaning you can have another if within one if block.

if (condition) {

    // Executes if condition is true

}

Decision statements determine the flow of the program

if-else statement

The if-else statement extends if by adding an alternative block of code that is executed if the condition is not met. This allows the program to choose between two possibilities.

if (condition1) {

    // Executes if condition is true

} else {

    // Executes if none of the conditions are true

}

if-else if- else statement

When it is necessary to check multiple conditions, a combination of if with one or more else if parts, with an optional final else, is used. This allows the program to branch into multiple possible outcomes.

 

if (condition1) {

    // Executes if condition1 is true

} else if (condition2) {

    // Executes if condition1 is false and condition2 is true

} else {

    // Executes if none of the conditions are true

}

What Are the Differences in If Statements Between the C Programming Language and Others?

Mastering Conditional Logic in PHP, Deep Dive into if, else and switch Statements

As a prerequisite to understanding conditional statements in PHP, a thorough comprehension of PHP operators is required. We have extensively covered operators in our previous lesson, which you can review here. We hope you've mastered operators, as they are often used in conjunction with if-else and switch-case statements. For instance, experienced programmers frequently use the ternary operator instead of a simple if-else statement. Make sure you're comfortable with operators before moving on to this lesson. Conditional expressions are a fundamental component of any programming language. In PHP programming language, conditional statements play a crucial role in controlling the flow of execution. They enable programs to branch based on specific conditions. In PHP, conditional statements are used to make decisions and execute different blocks of code depending on whether a certain condition is true or false. The most commonly used conditional statements in PHP programming language are:    

if statement

if-else statement

If-elseif-else statement

switch statement

A software engineer decides in advance which PHP conditional statements to use in her project

Conditional statements in PHP offer a flexible way to control the flow of program execution, making code dynamic and adaptable to various scenarios. If, else, elseif, switch, and even the ternary operator are the primary tools programmers use to implement condition-based logic. In the PHP programming language, they are most often used for the following scenarios:

Data validation:

• Checking if the user has entered the correct password

• Checking if the email address is in the correct format

• Checking if the selected option is valid

Controlling the flow of execution:

• Executing different parts of the code depending on the value of a variable

• Skipping certain parts of the code if a certain condition is met

• Repeating a certain part of the code until a condition is met (loops)

Displaying different content based on the user:

• Displaying a different page layout for logged-in and logged-out users

• Displaying different content based on the user's role (admin, moderator, user)

Creating simple calculators and games:

• Calculating results based on input data

• Checking if the user has guessed the correct answer

Form validation:

• Checking if all required fields are filled

• Checking if the data format is correct

Of course, you may have your own programming needs, too. As skilled as you are in using conditional expressions, in real day-to-day decisions, you are as good a programmer as you are.

What is an if-else Statement and How is It used?

Iskazi Odlučivanja u C# programskom jeziku

U prethodnom postu smo učili operatore poređenja i zahvaljujući poznavanju istih mi smo danas u mogućnosti da učimo iskaze odlučivanja. Zato je važno da ne preskačete postove već da učite redom jedan za drugim. Postovi na ovom blogu su povezani i omogućavaju vam da učite programiranje korak po korak. Važno je da isprogramirate sve primere. Ukoliko vam nešto nije dovoljno jasno ili ste zaboravite nešto što smo pre učili uvek se možete vratiti na neki od prethodnih postova. Ako imate neka pitanja uvek možete me pitati ovde. Takođe, iza svakog posta možete komentarisati sve što vas interesuje. Programiranje se uči programiranjem. Ali takođe treba da budete vredni i uporni. Profesionalni programeri programiraju skoro svaki dan godinama. Mnogi od njih imaju stotine svojih vlastitih malih programa koji rešavaju neke ključne male probleme i oni tačno znaju gde, kada i šta da koriste od koda i u velikim projektima. Takođe, uvek su zainteresovani za sve što je novo, bolje, praktičnije i jednostavnije. Ono što ih pokreće jeste upornost i što su sami inovativni. Uzmite bilo koji zadatak iz matematike i pokušajte sami da ga rešite na programerski način. Kad to uradite bićete ponosni sami na sebe što ste uspeli i zaista ćete se osećati srećno. Biti programer znači biti sposoban da rešite bilo koji problem na programerski način. Čak i ako ne znate kako da nešto isprogramirate, samo korak po korak i učenjem dolazite do rešenja. Programeri stalno uče i stalno ponavljaju naučeno.

( If ... else... statement ... iskaz odlučivanja )

Iskazi odlučivanja su bazirani na uslovima. Bez obzira koliko uslov bio kompleksan on se na kraju uvek svodi na boolean operator true - tačno ili  false – netačno. U programiranju je sve tačno ili netačno, ne postoji možda. Za iskaze odlučivanja koristimo if … else … iskaze ali i druge. Sintaksa if … else... ove komande je jednostavna:

if (uslov) iskaz;

Ponekad je mnogo bolje da prethodni iskaz pišete na sledeći način.

if (uslov)
{
        iskaz = true;

}

Ovo se uglavnom radi što ponekad postoji mogućnost da ćete imati u budućnosti više iskaza, pa je bolje ostaviti prostor za njih nego prepravljati if iskaz. U nekim kompanijama ovo je takođe obavezno da radite i kad mislite da za to nema potrebe.

if (uslov)
{

        iskaz1 = true;
        iskaz2 = true;
        iskaz3 = true;

}

Ponekad možete imati uslov koji će se izvršiti jedan iskaz ako je uslov tačan dok će izvršiti drugi iskaz ako nije tačan:

if (uslov)
{
        iskaz1;

}
else
{
        iskaz2;

}

Ponekad možete imate više uslova:

if (uslov1)
{
        iskaz1;

}
else if (uslov2)
{
        iskaz2;

}
else
{
        iskaz3;

}

Ponekad ćete hteti da u jednom uslovu, postavite drugi ili više njih i to možete da radite. To se zove grananje. Skoro sva AI - Artificial Intelligence – veštačka inteligencija je bazirana na iskazima odlučivanja i to je mnogo bitna stvar nego što vi sada možete i da pretpostavite. Iskazi odlučivanja se često koriste, skoro u svakom programu i one odlučuju tok celog vašeg programa. Takođe, vi ste jedino odgovorni ukoliko imate neke greške u očekivanim rezultatima tokom grananja if… else... iskaza i niko drugi.

Praktični primer If … else iskaza

If else statement i swich statement u C++ programskom jeziku

Odluke, odlučivanje i još kako ih programeri zovu grananje su najvažnija sposobnost računara da reaguju na različite uslove. I pored toga što računari ne razmišljaju kao ljudska bića ona perfektno i precizno donose jednostavne odluke. Računar će uvek tačno i precizno izvršiti svaku vašu naredbu čak i ako je vaša naredba besmislena. Instrukcije za odlučivanje zavise isključivo od programera.

 

( If else statement u C++ programskom jeziku )

Međutim ako pravilno unesete i sinhronizujete mnogobrojne odluke poput; ako prodajete više krušaka nego jabuka u prvoj trećini prodaje istih, onda spusti cenu jabuka za 10 procenata ili spustite cenu krušaka za 8 procenata. Nizom pravilno napisanih uslova, grananja; vaš program jednostavno postaje pametniji. Na sličan način se gradi i AI – ArtificialIntelligence – veštačka inteligencija. Najjednostavniji oblik if iskaza je:

if ( izraz ) iskaz;

Ovaj oblik se u kodu piše i ovako:

if ( izraz )
{
         iskaz;

}

Ako je A tačno onda uradi B. Pogledajte jednostavan primer. Ako imate 10 ili više kilograma jabuka onda obavesti korisnika:

#include "stdafx.h"

#include <iostream>

using namespace std;

int main()

{

       short apple = 0;

       cout << "How much do you weigh apples? ";

       cin >> apple;

       if (apple >= 10) cout << "You have 10 or even more kilos apples." << endl << endl;

       system("PAUSE");

       return 0;

}

Pogledajte šta se dešava kad pokrenemo ovaj program i unesemo vrednost 15: