Literals

A literal is a fixed value written directly in the source code. Its value is literally whatever you typed.

The common kinds

cpp
cout << 42 << '
';        // integer literal
cout << 3.14 << '
';      // floating-point literal
cout << 'A' << '
';       // char literal (single quotes)
cout << "hello" << '
';   // string literal (double quotes)
cout << true << '
';      // boolean literal

• 42 - an integer (whole number).
• 3.14 - a floating-point (number with a fraction).
• 'A' a char literal - one single character, single quotes.
• "hello" a string literal - text, double quotes.
• true - a boolean (true or false).

Why they matter

Literals are our "fixed data": unlike variables, they never change. Every price, name, or message that's always the same starts life as a literal.

Writing the bases (C++14)

Numbers can be written in other bases to make reading easier:

• Decimal: 42
• Octal, start with a 0: 052 (that's decimal 42).
• Hexadecimal, start with 0x: 0x2A (decimal 42).
• Binary, start with 0b (C++14+): 0b101010 (decimal 42).

Suffixes to fix type

A small letter after the number picks an exact type:

cpp
3.14f;    // float

### 42L;      // long

### 42U;      // unsigned

### 42ULL;    // unsigned long long

Use suffixes when you need a very specific type; otherwise the default is fine.

TL;DR

• A literal is a fixed value typed directly in the code.
• Kinds: integers 42, floats 3.14, chars 'A', strings "hello", booleans true.
• Number bases: 0 = octal, 0x = hex, 0b = binary (C++14+).
• Suffixes like f, L, U, ULL set the exact type.