DevAcademia lesson/C++ Basics

Printing Numbers

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~8 min lesson23 learning blocks4 code examples1 checks/interactions

Lesson outline

Outputting Numeric Values

The std::cout object handles all numeric types in C++ including integers and floating-point numbers, and supports scientific notation.

Key advantages:

Printing different numeric types:

std::cout prints the result of expressions (evaluated with normal operator precedence):

Use manipulators to control precision and notation. Flags and precision persist until changed:

Control integer base and presentation with stream flags:

For production code:

Initialize variables before output
Prefer '\n' for newlines; reserve std::endl (newline + flush) for when output must be immediately visible
Use constants for magic numbers
Consider locale-specific formatting where appropriate
For financial values, prefer fixed notation (std::fixed with std::setprecision(2)) and consider storing values in integer minor units (e.g., cents) to avoid floating-point rounding issues
For clearer booleans, use std::boolalpha (true/false instead of 1/0)
Avoid using namespace std; in global scope; qualify with std::

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