Execution Order

Execution order in Python

Programmers use languages to write instructions.
However, these instructions are usually ordered.

In python, order is done from up to bottom.
Run the following code:

print("Hello")
print("world!")

As you can see in the terminal, “Hello” is first printed, and then “world!” is printed.

Exercises

1.

Display the following on the terminal:

Coding
is 
fun

2.

Display the following on the terminal:

Coding is fun
but sleeping is nice too

Execution order in other languages

In other programming languages, backlines and spaces are actually ignored.
To separate instructions, we use the “;” character.
Instructions are running from left to right.
However, since backlines are ignored, writing from top to bottom also work, as long as we put the “;” character after each instruction.

It means that in C++, the following programs are valid and equivalent:

#include <iostream>

int main()
{
    std::cout << "Hello" << std::endl;
    std::cout << "world!" << std::endl;
}

#include <iostream>

int main() {
    std::cout << "Hello" << std::endl; std::cout << "world!" << std::endl;
}

#include <iostream>

int main()
{
            std::cout << "Hello" << std::endl
    ;
std::cout << "world!" << 
    std::endl
    ;
}

However, the code we write must be easily understandable by others.
If not, they wouldn’t be able to fix bugs related to your code in a bigger program.

That is why we usually come back to line after each instruction, as a good practice.
This is valid for C, C++, Java, C#, etc.

Exercises

Try doing the same exercises as before, but in other languages (C, C++, C#, Java).