If-Else-Elif Statements in Python

In Python, if-else-elif statements are used to control the flow of a program based on conditions. Here's a breakdown of how they work:

If Statement

The if statement is used to execute a block of code if a certain condition is true.

if condition:
2    # code to be executed if condition is true

Example:

x = 5
2if x > 10:
3    print("x is greater than 10")

In this example, the code inside the if block will not be executed because the condition x > 10 is false.

If-Else Statement

The if-else statement is used to execute a block of code if a certain condition is true, and another block of code if the condition is false.

if condition:
2    # code to be executed if condition is true
3else:
4    # code to be executed if condition is false

Example:

x = 5
2if x > 10:
3    print("x is greater than 10")
4else:
5    print("x is less than or equal to 10")

In this example, the code inside the else block will be executed because the condition x > 10 is false.

If-Elif-Else Statement

The if-elif-else statement is used to execute a block of code if a certain condition is true, another block of code if the first condition is false and a second condition is true, and another block of code if both conditions are false.

if condition1:
2    # code to be executed if condition1 is true
3elif condition2:
4    # code to be executed if condition1 is false and condition2 is true
5else:
6    # code to be executed if both conditions are false

Example:

x = 5
2if x > 10:
3    print("x is greater than 10")
4elif x == 5:
5    print("x is equal to 5")
6else:
7    print("x is less than 5")

In this example, the code inside the elif block will be executed because the condition x > 10 is false, and the condition x == 5 is true.

Nested If-Else Statements

If-else statements can be nested inside each other to create more complex conditional logic.

condition1:
2    if condition2:
3        # code to be executed if both conditions are true
4    else:
5        # code to be executed if condition1 is true and condition2 is false
6else:
7    # code to be executed if condition1 is false

Example:

x = 5
2y = 10
3if x > 5:
4    if y > 10:
5        print("x is greater than 5 and y is greater than 10")
6    else:
7        print("x is greater than 5 but y is less than or equal to 10")
8else:
9    print("x is less than or equal to 5")

In this example, the code inside the inner if block will not be executed because the condition x > 5 is false.

I hope this helps! Let me know if you have any questions or need further clarification.

Question: Write a Python program to determine the type of a triangle based on the lengths of its sides. The criteria are as follows:

• If all sides are equal, the triangle is equilateral

• If two sides are equal, the triangle is isosceles

• If no sides are equal, the triangle is scalene

• If the sum of the lengths of any two sides is less than or equal to the length of the third side, the triangle is not valid

Task: Write a Python program using if-else-elif statements to determine the type of a triangle based on the lengths of its sides.

Input: The lengths of the three sides of the triangle (three integer values)

Output: The type of the triangle (equilateral, isosceles, scalene, or not valid)

Go ahead and try to solve it!