Question

What does this program print? $$ \begin{aligned} &\text { print }\left(" 39+3^{\prime \prime}\right) \\ &\text { print }(39+3) \end{aligned} $$

Short answer

The program prints ' 39+3' and then 42.

Step-by-step solution

Analyze the First Print Statement

Look at the first print statement: \(\text{print}(" 39+3^{\prime \prime}").\) This statement prints a literal string, so it will output the exact text inside the quotation marks: ' 39+3'. No arithmetic operation is performed here because it is treated as a string.

Analyze the Second Print Statement

Examine the second print statement: \(\text{print}(39+3).\) Unlike the first, this one contains an arithmetic operation without quotation marks, so it will perform the addition operation. Hence, it will calculate \(39 + 3 = 42\) and print the result 42.

Key concepts

Print Statement

In Python, the `print` statement is a fundamental tool used to display information to the console. It allows you to output data and messages so that you, or anyone reading your program, can understand the program's behavior. The syntax for the `print` statement is straightforward, typically written as `print(expression)`. This expression can be many things, such as a string literal, a variable, or even the result of an arithmetic operation.

• If the expression is enclosed in quotes (single or double), it will treat it as a string literal and print exactly what is inside the quotes.
• Without quotes, Python interprets it as an expression and performs any operations required before printing the result.

Understanding `print` is crucial in developing programs because it provides insight into what the program is doing at any given time.

String Literal

String literals in Python are sequences of characters enclosed by quotes, single ('') or double (""). They are one of the simplest data types in Python used to represent textual data. For example, in the statement `print("Hello, World!")`, "Hello, World!" is a string literal.
When using string literals:

• Everything inside the quotes is treated as text, even numbers or operators.
• No calculations or modifications are made to the string content; it is output exactly as it appears.

Python also supports various string operations such as concatenation, slicing, and formatting, which enhance the way you can manipulate text in your programs.

Arithmetic Operation

Arithmetic operations are essential parts of any programming language, including Python. These operations involve basic mathematical functions such as addition, subtraction, multiplication, and division. In the `print` statement `print(39 + 3)`, Python performs the arithmetic operation of addition.
The steps involved are:

• Identify the numbers and the operation sign, in this case, `39`, `+`, `3`.
• Perform the indicated operation, which results in the computation: 39 + 3 = 42.
• The result of this operation is then passed to the `print` function, which outputs `42` to the console.

Python follows the rules of arithmetic precisely, so understanding these operations is fundamental to performing any calculations in your code.

Debugging

Debugging is the process of identifying and fixing issues or bugs in your code. It is an essential skill for every programmer. When things don't work as expected, debugging helps track down the problem source. Efficiently using print statements is a simple but effective way to debug.
To debug with print statements:

• Insert `print` at key locations in your code to check the state of variables and the flow of execution.
• Use descriptive messages in your print outputs to clarify what you are displaying, e.g., `print("Value of x:", x)`.

This straightforward method can pinpoint logical errors or places where the program's actual output differs from the intended outcome. Mastering debugging increases productivity and reduces frustration, making development smoother and more efficient.