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# '▶︎ Run' button to execute and enter a number

# Get user age
user_age = input("Please enter your age in numbers: ")

# Convert the entered age from string → integer
age = int(user_age)

# Calculate age for next year
next_year_age = age + 1

# Print the results
print("Current age:", age)
print("Age next year:", next_year_age)

# Note: Use a conditional statement to print different messages based on age
if age < 20:
    print("You are a teenager. Have a great day!")
else:
    print("You are an adult. Have a great day!")

# How to Talk to a Computer: Input and Output

Computer programs interact with users and perform tasks based on their requests.

To do this, programs receive data from the user and the external world as **input** and return results as **output**.

In Python, the `input()` function is used to receive input from the user, and the `print()` function is used to output results.

<br />

## Getting Input from the User with input

When you need to ask the user something and receive a response, use the `input()` function.

For example, you can ask, "What is your name?" and have the user input their name through the program.

```python title="Getting User Input"
name = input("What is your name? ")

print(name)
```

When you run the code above, the computer will ask "What is your name?" and print the name entered by the user.

<br />

> Note: The `input()` function always returns the input as a **string**.

If you want to handle numerical operations after receiving numbers from the user, you should wrap the input value with the `int()` function to convert it to a number.

```python title="Processing Numerical Input"
# Convert the input age to an integer using int
user_age = input("How old are you? ")
age = int(user_age)

# Add 1 to the input age to calculate the age next year
next_year = age + 1

# Print the age next year: input age + 1
print(next_year)
```

<br />

## Displaying Results with print

As seen in the previous example, to make the computer output something, use the `print()` function.

This function is used to display results on the screen, and you can also print multiple values at once.

```python title="Printing"
print("Python is", "really", "fun!")
```

In the code above, multiple strings are separated by commas and printed on one line, with the comma-separated values connected by a space.

Therefore, this code will print "Python is really fun!".

We will learn more about the print function in the next lesson.

The `input()` function always returns the user input as a string. This means that even if the user inputs a number, it will be treated as a string and may require additional conversion.

### Communicating with the Computer: Input and Output