Whitespace and Formatting

What is Whitespace?

Whitespace includes spaces, tabs, and newlines. In C++:

• Whitespace is mostly ignored by the compiler
• It's crucial for code readability
• Good formatting makes code easier to understand and debug

Whitespace Rules

Required Whitespace

Some whitespace is required to separate keywords and identifiers:

// Required spaces
int x;           // Space between 'int' and 'x'
return 0;        // Space between 'return' and '0'

// Would cause errors without spaces
intx;            // Looks like variable name 'intx'
return0;         // Looks like variable name 'return0'

Optional Whitespace

Most whitespace is optional but improves readability:

// Minimal whitespace (legal but hard to read)
int x=5;int y=10;cout<<x+y<<endl;

// Better formatting
int x = 5;
int y = 10;
cout << x + y << endl;

Whitespace in Quoted Text

Whitespace inside string literals (quoted text) is treated differently - it's preserved exactly as written:

cout << "Hello World";        // One space between words
cout << "Hello  World";       // Two spaces preserved
cout << "Hello\tWorld";       // Tab character preserved
cout << "Hello\nWorld";       // Newline character preserved
cout << "Hello                    World";  // Large amount of whitespace preserved
cout << "Name:        John Doe";          // Spacing for alignment preserved

Multiple Lines in Strings

// This won't compile - strings can't span multiple lines
cout << "This is a very long string that I want to
         continue on the next line";

// Use concatenation instead
cout << "This is a very long string that I want to "
     << "continue on the next line";

// Or escape sequences
cout << "Line 1\nLine 2\nLine 3";

Escape Sequences for Whitespace

Common escape sequences for whitespace:

cout << "Tab:\tSeparated text";     // \t = tab
cout << "New line:\nNext line";     // \n = newline
cout << "Quote: \"Hello\"";         // \" = literal quote
cout << "Backslash: \\path";        // \\ = literal backslash

Formatting Guidelines (Style Guide)

Spaces Around Operators

// Hard to read
int result=x+y*z-5;

// Much better
int result = x + y * z - 5;

Spaces After Commas

// Cramped
cout<<"Values: "<<x<<","<<y<<","<<z<<endl;

// Readable
cout << "Values: " << x << ", " << y << ", " << z << endl;

One Statement Per Line

// Hard to read
int x=5;int y=10;cout<<x+y;

// Much better
int x = 5;
int y = 10;
cout << x + y;

Indentation

Use consistent indentation to show code structure:

Function Bodies

int main() {
    cout << "Hello World" << endl;
    int x = 5;
    cout << "x = " << x << endl;
    return 0;
}

Nested Blocks

int main() {
    int x = 10;
    if (x > 5) {
        cout << "x is greater than 5" << endl;
        cout << "The value is: " << x << endl;
    }
    return 0;
}

Blank Lines

Use blank lines to separate logical sections:

#include <iostream>

int main() {
    // Get user input
    int age;
    cout << "Enter your age: ";
    cin >> age;

    // Process the input
    bool isAdult = (age >= 18);

    // Display result
    if (isAdult) {
        cout << "You are an adult." << endl;
    } else {
        cout << "You are a minor." << endl;
    }

    return 0;
}

Common Brace Formatting Styles

Style 1: Braces on New Line

int main()
{
    if (condition)
    {
        cout << "Hello" << endl;
    }
}

Style 2: Braces on Same Line (More Common)

int main() {
    if (condition) {
        cout << "Hello" << endl;
    }
}

Consistency is Key

• Pick one style and stick with it
• Follow your team's or project's conventions
• Good formatting becomes a habit

Why Formatting Matters

Readability

// Unformatted - hard to understand
if(x>0){if(y>0){cout<<"Both positive"<<endl;}else{cout<<"X positive, Y not"<<endl;}}

// Formatted - easy to understand
if (x > 0) {
    if (y > 0) {
        cout << "Both positive" << endl;
    } else {
        cout << "X positive, Y not" << endl;
    }
}

Debugging

Well-formatted code makes it easier to:

• Spot errors
• Add debug output
• Understand program flow
• Collaborate with others

Choosing a Style

For beginners, we recommend:

// Simple, readable style
int main() {
    int userAge;
    cout << "Enter your age: ";
    cin >> userAge;

    if (userAge >= 18) {
        cout << "You are an adult." << endl;
    } else {
        cout << "You are a minor." << endl;
    }

    return 0;
}

Key principles:

• Use camelCase for variables and functions
• Put braces on the same line
• Use 4 spaces for indentation
• Be consistent throughout your code

Summary

Whitespace is essential for readable C++ code. Key principles:

• Required whitespace: Separates keywords and identifiers (int x, not intx)
• Optional whitespace: Improves readability around operators and commas
• Indentation: Shows code structure and nesting levels consistently
• One statement per line: Makes code easier to read and debug
• Blank lines: Separate logical sections of code
• String literals: Preserve whitespace exactly as written
• Consistency: Choose a formatting style and stick with it

Good formatting makes your code professional, readable, and maintainable. Most IDEs can auto-format your code, but understanding these principles helps you write better code from the start.