Compilation and execution flow in Rust - Step-by-Step Execution

Concept Flow - Compilation and execution flow

Write Rust source code

↓

rustc compiler reads code

↓

Syntax and semantic checks

↓

Generate executable

↓

Run executable

↓

Program output on screen

This flow shows how Rust code is written, compiled into an executable, and then run to produce output.

Execution Sample

Rust

fn main() {
    println!("Hello, Rust!");
}

This simple Rust program prints 'Hello, Rust!' to the screen.

Execution Table

Step	Action	Evaluation	Result
1	Write source code	Code with fn main and println!	Source file created
2	Run rustc compiler	Check syntax and semantics	No errors found
3	rustc generates executable	Translate code to machine instructions	Executable file created
4	Run executable	Start program execution	Program runs
5	Execute main function	Call println! macro	Prints 'Hello, Rust!'
6	Program ends	No more instructions	Process exits
7	Output displayed	Captured stdout	Hello, Rust!

💡 Program finishes after main function completes and output is shown.

Variable Tracker

Variable	Start	After Compilation	After Execution	Final
source_code	empty	Rust code text	Rust code text	Rust code text
executable	none	created	running	finished
output	none	none	Hello, Rust!	Hello, Rust!

Key Moments - 3 Insights

Why do we need to compile Rust code before running it?

Rust is a compiled language, so the source code must be translated into machine code by rustc before the computer can run it. This is shown in steps 2 and 3 of the execution table.

What happens if there is a syntax error in the code?

The compiler finds errors during the syntax and semantic checks (step 2). It stops and shows error messages instead of creating an executable, so the program cannot run.

When does the program actually produce output?

Output is produced during execution of the main function (step 5), when the println! macro runs and prints text to the screen.

Visual Quiz - 3 Questions

Look at the execution table, at which step is the executable file created?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Check the 'Action' and 'Result' columns in the execution table for when the executable is generated.

According to the variable tracker, what is the state of 'output' after compilation but before execution?

A Rust code text

B Hello, Rust!

C none

D created

💡 Hint

Look at the 'output' row in variable_tracker under 'After Compilation' column.

If a syntax error occurs, which step in the execution table would NOT happen?

A Step 3

B Step 1

C Step 2

D Step 5

💡 Hint

Errors stop the process before executable creation, so step 3 is skipped.

Concept Snapshot

Rust compilation flow:
1. Write source code (fn main)
2. Compile with rustc (syntax check + machine code)
3. Create executable file
4. Run executable (main runs)
5. Output printed by println!
6. Program ends

Full Transcript

This visual execution shows how Rust code is written, compiled, and run. First, you write the source code with a main function. Then, the rustc compiler checks the code for errors. If no errors are found, it creates an executable file. Running this executable starts the program, which executes the main function. Inside main, the println! macro prints text to the screen. After printing, the program finishes and exits. Variables like source_code, executable, and output change state during these steps. If there is a syntax error, the compiler stops and shows errors before creating an executable. This flow helps beginners understand the step-by-step process from code to output in Rust.