Conditional Statements

Conditional statements control the flow of a program by executing certain pieces of code only when specific conditions are met. Here, we discuss three main types of conditional statements in programming: if, else, and elif.

If Statement

The if statement is a control flow statement that allows code to run only when a particular condition is satisfied.

Syntax

if (condition):
    # body of if

Example

age = 18
if age >= 18:
    print("You are eligible to vote.")

In this example, the message "You are eligible to vote." will be printed only if the condition age >= 18 is true.

Reference Code

Else Statement

The else statement follows an if statement and runs a block of code if the if condition is false.

Syntax

if (condition):
    # body of if
else:
    # body of else

Example

age = 16
if age >= 18:
    print("You are eligible to vote.")
else:
    print("You are not eligible to vote.")
In this example, the message "You are not eligible to vote." will be printed because the condition age >= 18 is false.

Note No condition is required for the else statement. It acts as a catch-all for any scenario where the if condition is not met.

Reference Code

Elif Statement

The elif statement allows you to check multiple conditions. It stands for "else if" and is used when you want to test more than two conditions.

Syntax

if (condition):
    # body of if
elif (condition):
    # body of elif
elif (condition):
    # body of elif
...
else:
    # body of else

Example

score = 75
if score >= 90:
    print("Grade: A")
elif score >= 80:
    print("Grade: B")
elif score >= 70:
    print("Grade: C")
else:
    print("Grade: D")

In this example, the message "Grade: C" will be printed because the score of 75 meets the condition score >= 70.

Note Just like with else, no condition is required for the final else block. It will execute if none of the preceding if or elif conditions are met.

Reference Code

Complete Example

Here's a complete example demonstrating the use of if, else, and elif statements in a single block of code:

age = 20
score = 85

# Checking voting eligibility
if age >= 18:
    print("You are eligible to vote.")
else:
    print("You are not eligible to vote.")

# Checking grade based on score
if score >= 90:
    print("Grade: A")
elif score >= 80:
    print("Grade: B")
elif score >= 70:
    print("Grade: C")
else:
    print("Grade: D")

This example first checks if a person is eligible to vote based on their age, and then it checks the grade based on their score. It demonstrates how to use if, else, and elif statements effectively to control the flow of a program.