Your first program, line by line

The smallest complete program

using System;

public class Solution
{
    public static void program()
    {
        Console.WriteLine("Hello, Code Journey!");
    }
}

Every line has a job:

| Line | Job | |---|---| | using System; | make the System namespace's types visible by short name (Console lives there) | | public class Solution | declare a class — C# code always lives inside a type | | public static void program() | declare a method: a named, reusable block of code | | Console.WriteLine(...) | a statement — one instruction; note the semicolon | | { } | braces group code into blocks |

Namespaces are named groups of types — folders for code. Console is System.Console; using System; lets you write just Console. Fully-qualified System.Console.WriteLine(...) works identically. This course's challenge boilerplate already includes the common using lines; you focus on the code inside.

Strings are text in double quotes. "Hello" is a string literal. Single quotes make a char (one character) — 'A' and "A" are different types.

Output that isn't one line

Console.Write prints without a newline; Console.WriteLine prints and moves to the next line. Mixing them builds rows:

Console.Write("Score: ");
Console.WriteLine(97);        // "Score: 97" on one line
Console.WriteLine();          // empty line

Comments are for humans; the compiler ignores them:

// a single-line comment
/* a block comment
   spanning lines */

Write comments for the why, not the what — the code already says what it does.

Escape sequences

Some characters need a backslash escape inside strings: \n (newline), \t (tab), \" (quote), \\ (backslash). "She said \"hi\"\n" prints She said "hi" and a line break.