#9: If Else Statements in C | C Programming for Beginners

Summary

In this educational C programming video, Padma from 'Programmies' introduces the concept of if-else statements, crucial for decision-making in code. The tutorial covers syntax, usage, and examples like checking voting eligibility based on age. It progresses to demonstrate else and else-if clauses for multiple conditions, enhancing logic with logical operators. The video concludes with a programming challenge to check if a number is positive, negative, or zero, encouraging viewers to apply their newfound knowledge.

Takeaways

• 📝 The video is a tutorial on 'if else' statements in C programming, focusing on decision-making in code.
• 🔍 It explains the syntax and usage of 'if' statements, which execute code based on a boolean condition being true or false.
• 👤 The tutorial uses a real-world example involving an election where the age of a person determines their eligibility to vote.
• 📈 The script demonstrates how to implement an 'if' statement to check if a person's age is 18 or above to print a message about eligibility.
• 📑 It shows the process of taking user input for the age variable and using 'printf' and 'scanf' statements in C.
• 🔄 The video covers the use of 'if' statements with 'else' clauses to handle scenarios where the condition is not met, like printing a message for ineligible voters.
• 🔧 The script introduces 'else if' clauses for handling multiple conditions, allowing the program to make decisions based on more than two options.
• 🔑 The tutorial provides a practical example of using 'else if' to check for invalid age values like being less than 0 or greater than 120.
• 💡 It offers a tip on simplifying 'if' and 'else' blocks by omitting curly braces when there's only one statement to execute.
• 📚 The video encourages viewers to practice creating test conditions and to review comparison and logical operators for building these conditions.
• 🎯 The script concludes with a programming challenge for viewers to create a program that checks if a number is positive, negative, or zero.

Q & A

What is the purpose of the 'if else' statement in C programming?

The 'if else' statement in C programming is used for decision making, allowing a program to perform different sets of tasks based on whether a condition is true or false.

What is the basic syntax of an 'if' statement in C?

The basic syntax of an 'if' statement in C is 'if (test condition)' followed by the body of the statement. The test condition is a boolean expression that evaluates to either true or false.

What happens if the test condition in an 'if' statement is true?

If the test condition in an 'if' statement is true, the body of the 'if' statement is executed. If it is false, the body is skipped.

Can you provide an example of how to use an 'if' statement to check a person's eligibility to vote based on age?

Yes, you can create a variable to store the person's age, ask the user to input their age using 'printf' and 'scanf', and then use an 'if' condition to check if the age is greater than or equal to 18. If true, print 'You are eligible to vote'.

What is the purpose of an 'else' clause in an 'if' statement?

The 'else' clause in an 'if' statement is used to execute a different block of code when the test condition of the 'if' statement is false.

How can you modify the voting eligibility program to also handle cases where the age is less than 18?

You can add an 'else' clause to the program that prints 'Sorry, you are not eligible to vote' when the age is less than 18.

What is the syntax for an 'if' statement with an 'else if' clause?

The syntax for an 'if' statement with an 'else if' clause is 'if (test condition 1) { ... } else if (test condition 2) { ... }'. The program checks each condition sequentially and executes the block of code corresponding to the first true condition.

Why might you use 'else if' clauses instead of multiple 'if' statements?

Using 'else if' clauses instead of multiple 'if' statements can make the code more efficient by avoiding repetitive checks of the same conditions and ensuring that only one block of code is executed.

Can you provide an example of using 'else if' clauses to handle multiple conditions in a program?

Yes, in the voting eligibility program, you can use 'else if' clauses to check if the age is greater than 120 or less than 0, and print 'Invalid age' for both conditions.

What is the advantage of using logical operators in 'if else' statements?

Using logical operators in 'if else' statements allows you to combine multiple conditions into a single test condition, making the code more concise and easier to read.

What is the final programming challenge presented in the video script?

The final programming challenge is to create a program that checks whether a number is positive, negative, or zero using an 'if' statement based on user input.

How can you simplify an 'if else' block if it contains only one statement?

If an 'if else' block contains only one statement, you can omit the curly braces, making the code less cluttered and easier to read.

Where can viewers find the answers to the programming challenge and additional resources for learning C programming?

Viewers can find the answers to the programming challenge and additional resources on the GitHub repository mentioned in the video script, as well as on the website programmings.com.

Outlines

00:00

📝 Introduction to If-Else Statements in C Programming

This paragraph introduces the concept of decision making in C programming using if-else statements. It explains the syntax and usage of the if statement, which involves a boolean expression that evaluates to true or false. If the condition is true, the code block within the if statement is executed; otherwise, it is skipped. The paragraph provides an example of an election scenario where the program checks if a person's age is 18 or more to determine eligibility to vote. The example includes user input through printf and scanf functions and demonstrates how the if statement is used to print a message based on the age condition. It also touches on the limitations of using multiple if statements and hints at the use of else to handle conditions when the initial condition is not met.

05:02

🔁 Enhancing Decision Making with Else and Else If Clauses

This paragraph delves deeper into the if-else statement by introducing the else clause, which provides an alternative set of instructions to execute when the if condition is false. It explains the syntax and logic of using else in the context of the voting eligibility example, where a message is displayed if a person is not eligible to vote due to being under 18. The paragraph then extends the discussion to handle more complex decision-making scenarios with the else if clause, allowing for multiple conditions to be checked sequentially. It demonstrates how to modify the code to include additional conditions, such as invalid ages being greater than 120 or less than 0, and how to use logical operators to combine conditions for efficiency. The summary emphasizes the importance of understanding the logic behind test conditions and encourages practice to improve skill in creating them.

10:06

🔧 Practical Application and Simplification of If-Else Blocks

The final paragraph focuses on the practical application of if-else statements, including a tip on simplifying the syntax when the if-else block contains only a single statement, allowing the omission of curly braces. It also presents a programming challenge for the viewer to create a program that checks if a number is positive, negative, or zero, using an if statement based on user input. The paragraph encourages viewers to check the provided resources, such as the GitHub repository and the website programmings.com, for answers and further learning on nested if-else statements. It concludes with an interactive element, inviting viewers to comment their answers to a code output question and expresses well-wishes for continued learning and programming.

Keywords

💡if statement

The 'if statement' is a fundamental control flow mechanism in programming used to execute a block of code based on a condition. In the context of the video, it is used to determine whether a person is eligible to vote based on their age. The script provides an example where the if statement checks if a person's age is 18 or more to print a message about eligibility.

💡else clause

The 'else clause' is a part of the if statement that specifies a block of code to be executed if the condition in the if statement evaluates to false. In the video, it is used to print a message indicating ineligibility to vote when a person's age is less than 18.

💡boolean expression

A 'boolean expression' is an expression that results in either true or false. In the video, the boolean expression is used within the if statement to test whether the age is greater than or equal to 18, serving as the condition for the if statement.

💡decision making

The term 'decision making' refers to the process of selecting from one or more alternatives based on a set of conditions. The video script discusses how the if else statement in C programming is used for decision making, such as determining voting eligibility.

💡scanf statement

The 'scanf statement' is a standard input function in C used to read data from the standard input (usually the keyboard). In the script, it is used to take the user's input for the age, which is then used in the if statement to make a decision.

💡printf statement

The 'printf statement' is a standard output function in C used to display data to the standard output (usually the screen). The video script uses printf to print messages to the user, such as prompts and results of the if statement evaluation.

💡logical operator

A 'logical operator' is a symbol or keyword that represents a logical operation, such as AND, OR, and NOT. In the video, logical operators are used to combine conditions in the if statement, such as checking if the age is both greater than 120 or less than 0.

💡else if clause

The 'else if clause' is used in if statements to check multiple conditions in sequence. If the initial condition is false, the program checks the next condition in the else if clause. The video script demonstrates using else if to handle multiple age-related conditions for voting eligibility.

💡programming challenge

A 'programming challenge' is a task or problem set to test and improve one's programming skills. The video script ends with a programming challenge for the viewers to create a program that checks if a number is positive, negative, or zero using if statements.

💡nested if else statement

A 'nested if else statement' refers to an if or else if statement that is placed inside another if or else if statement. Although not covered in detail in the video, the script mentions that nested if else statements can be used for more complex decision making processes.

Highlights

Introduction to if else statement in C programming for decision making.

Syntax of the if statement explained with an example of an election scenario.

Demonstration of a basic C program to check if a person is eligible to vote based on age.

Explanation of how the if statement executes based on the boolean expression result.

Running the program with different age inputs to show the if statement in action.

Improving the program by adding an else statement to handle cases where the age is less than 18.

Use of else clause to print a message when a person is not eligible to vote.

Introduction of the else if clause for handling multiple decision-making paths.

Syntax and functionality of the else if clause explained with a voting eligibility example.

Modification of the program to include additional conditions for invalid ages.

Combining conditions using logical operators to simplify the if else structure.

Running the modified program to demonstrate the new conditions in action.

Tip on omitting curly braces for single-statement if else blocks.

Emphasis on the importance of practice in creating effective test conditions.

Programming challenge presented to check if a number is positive, negative, or zero.

Invitation to find answers and further resources on GitHub and the Programmings website.

Teaser for the next video and a call to action for engagement and support.

Programming squeeze segment inviting viewers to comment their answers to a code output question.

Transcripts

hey guys this is me padma from

programmies and welcome back to this

series on c programming in this video

we'll learn about if else statement in c

programming we'll learn to create

decision making programs that perform

one set of tags under a certain

condition and another set of tags under

different condition so let's get started

in c programming we use the if statement

to create programs that can make

decision let's start by looking at the

syntax of the if statement the if

statement starts with if keyword and is

followed by the test condition inside

the parenthesis

this test condition is a boolean

expression that results in either true

or false

if the test condition is true the body

of if statement is executed otherwise it

is skipped from the execution

now that you know the syntax of if

statement let's try a working example

suppose there is an election going on

and to cast the vote your a's must be 18

or more if your age is 18 or more we'll

print you are eligible to vote let's see

how we can implement this here i have a

basic c program now i'll create a

variable to store is

int is

now i'll ask the user to input there is

for that i'll use printf statement

and print the message like

enter

here is

then i'll use scanf statement to take

the input

so percent d

comma

ampersand is

then i'll use if condition to check if

a's is greater than or equals to 18.

if this condition is true i'll print

you are

eligible

to vote

now let me run this program

here i'll provide 31 as the is and i'll

press enter as you can see

you are eligible to vote is printed

here the value is 31 so our test

condition is greater than or equals to

18 is true that is why this print

statement

is executed

now let me run this program again

this time instead of 31 i'll enter 15

this time nothing is printed on the

screen this is because the a's is 15 so

the test condition is is greater than or

equals to 18 is false so the body of the

if statement is skipped

our program is working fine but it is

not printing anything when the a's is

less than 18. we might want to print

something like sorry you are not

eligible to vote when age is less than

18 so i'll add another if statement

so i'll say

if

is is less than 18

i'll print

sorry

you are not

eligible

to vote

now i'll run this code

and i'll enter 15 again

here you can see sorry you are not

eligible to vote is printed this is

because ace is 15 so this condition is

is greater than or equals to 18 is false

therefore the statement

is

skipped however this condition is is

less than 18 is true so this statement

is executed

by the way if you are watching this

there is a good chance you want to

improve your skill in c programming

lucky for you we have a mobile app that

provides a well-structured c programming

course with certification at the end and

you can use the app alongside the video

to practice on the built-in compiler our

course is free so download now by

scanning this qr code or click the link

in the video description

i have this code from the last segment

i'll remove this code to get the user

input

and i'll manually assign the value of is

equals to 15

so that it's easier to focus on the

logic of the if statement in this

program i have used two if statement to

perform two different tags

we know that the person is eligible to

vote only if the a's is greater than or

equals to 18 and if the condition is not

met we know that the person is not

eligible to vote

in such cases instead of writing the

second if statement with the condition

we can use else clause

let's first look at the syntax of the if

statement with the else clause

on your screen you can see how it looks

so what happens here is if our test

condition is true

statement inside the body of if

statement is executed and if it is false

statements inside the body of else are

executed

now getting back to our code to check if

the person is eligible to vote or not

in this program i'll use the else clause

instead of this second if statement so

i'll remove the second if statement and

replace it with

else

now let me read this code in plain

english as is greater than or equals to

18 then print you are eligible to vote

else print sorry you are not eligible to

vote now when i run this code

you can see sorry you are not eligible

to vote is printed

this is because ace is 15 which is not

greater than or equals to 18

so we get the output sorry you are not

eligible to vote

okay guys we need your support to keep

this type of content free for all user

youtube really likes engagement on the

video so leave a comment below press

that like button hit subscribe if you

haven't already let's get the engagement

score high up so that more people can

discover and enjoy these courses

the if statement with else clause allow

us to make a choice from two different

options however sometimes we need to

make choice from more than two options

in those case we can use elsif's clause

with test condition

let's see the syntax first

the if statement checks the first

condition inside the if statement if it

is true the body of if is executed and

the statement 2

and the statement 3 are skipped however

if the first test condition is false the

control of the program jumps to the

second test condition

if this condition is true the body of

the else if statement is executed and

other statement are skipped if both the

test condition 1 and the test condition

2 are false

then only the else body is executed

if necessary we can add as many else if

clauses as we want for our program to

work and among all those alternatives

only a single block of code is executed

now we know how the else if clause works

let's get back to our code to check

whether a person can vote or not

here the is variable stores the a's of

the person currently the is of oldest

person is 120 so i want this program to

consider is greater than 120 as invalid

similarly the a's cannot be negative so

i also want to write less than 0 as

invalid

now i want to include this two

additional condition in our program for

that i'll use else if clause now i'll

modify this code

so

if

a's is

greater than 1 and 20

i'll print

invalid is

invalid

is

and

as if

so if a's is

less than 0

that is negative value then will print

is

invalid

is

i'll change this if to elsif

so as you can see i have included one if

condition

two else if condition

and finally one else condition

here i'll change the value from 15 to

130

now i'll run this code

here the a's is greater than 120 so we

get invalid is as our output

now let's change the value of this is

from 130 to minus 4 and let's run this

again

this time we get invalid is again

so this is the condition of else if here

is is less than zero so the output we

got is invalid is

now we can add as many else if condition

as we want here we can see these two

condition are performing the same tags

printing the invalid is

in this case we can combine both the

condition together using logical

operator

here the a's is invalid if it is either

greater than 120 or less than 0 or let

me modify this code so i'll cut this

i'll use logical r and put here

is

less than 0. so i'll change this value

from -4 to -1 and when i run this code

i get invalid is as output

now as long as the a's is an integer

number our program works correctly and

the extra condition make sure the a's is

neither greater than 120 or less than 0

and for any other value of a's the

program runs as intended if we provide

the is equals to 50 so let's do that

i'll provide the value of a is equals to

50 i'll run this

now this person is eligible to vote

before we end this video one quick tip

for you if the body if else block has

only one statement like this then we can

omit the curly braces of the if block

like this

as you can see the syntax of the if

statement is pretty simple the harder

part is the logic behind the test

conditions so you will get better at

creating test condition with practice

also be sure to check our video on the

comparison and logical operators that

are used to create the test condition

the link will be in the video

description below

we have covered a lot in this video it's

time for you to practice what we have

learned here is one programming

challenge for you to solve can you

create a program to check whether a

number is positive negative or zero to

create this program create a variable

named number and assign a double value

to it based on the user input then using

an if statement check if the number

variable is positive negative or zero

if the number is positive print the

number is positive if the number is

negative print the number is negative

and if the number is 0 print the number

is 0. you'll find all the answers to

this question in our github repository

and also if you want to revise the

concept we'll learn today you can find

all programs in the repository since the

video is already long we are not

covering the nested if else statement if

you are interested you can learn about

them from our website programmings.com

i'll put the link in the video

description

now that we are at the end of this video

it's time for programming squeeze

what is the output of following code

comment your answer below and see you on

the next video happy programming

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