Nesso Academy Lecture: Types of Literal Constants in C++

Overview

In this lecture, we delve into the different types of literal constants available in C++. This extends from the foundational concepts of literal constants discussed in previous lectures.

Key Topics

1. Integer Literal

• Definition: An integer literal is a number without a fractional part.
• Notations:
  • Decimal Notation: Default method, digits from 0 to 9.

    int A = 10;
    

  • Hexadecimal Notation: Prefix 0x, digits from 0 to 9 and A-F.

    int B = 0x1A; // 26 in decimal
    

  • Octal Notation: Prefix 0, digits from 0 to 7.

    int C = 032; // 26 in decimal
    

  • Binary Notation: Prefix B, digits 0 and 1.

    int D = B1010; // 10 in decimal
    

• Suffixes:
  • u or U: Unsigned integers.
  • l or L: Long integers.
  • ul, Lu: Unsigned long integers.
  • ll or LL: Long long integers.
  • ull, LLU: Unsigned long long integers.

2. Floating Point Literal

• Definition: Represents a number with a fractional part or in exponential form.
• Examples:
  • Double literals (default for floating-point literals): 4.5
  • Float literals (using f or F): 4.5f

    double X = 4.5;
    float Y = 4.5f;
    

• Exponential Form: Uses e for scientific notation.

  double Z = 5.2e5; // 5.2 * 10^5
  

3. Character Literal

• Definition: A single character enclosed in single quotes ('A').
• Examples:
  • Character: 'A'
  • Escape characters (e.g., newline): '\n'
• Internal Storage: Stored as integers based on ASCII values (e.g., 'A' is 65 in ASCII).
• Arithmetic Operations: Can perform arithmetic operations due to integer storage.

4. String Literal

• Definition: A sequence of characters enclosed in double quotes ("Hello").
• Examples:
  • const char* name = "Alice";
  • std::string greet = "Hello World";
• Characteristics:
  • Implicit null terminator (\0) at the end.
  • Concatenation of string literals when on separate lines.

5. Boolean Literal

• Definition: Represents either true or false.
• Examples:
  • bool isReady = true;
  • bool isEmpty = false;
• Internal Representation:
  • true is equivalent to 1.
  • false is equivalent to 0.
• Conversion: Nonzero values convert to true.

Conclusion

This lecture covers the types and representations of literal constants in C++. Understanding these types are crucial for effective programming in C++. Thank you for participating in this session. The next lecture will continue to expand on these concepts.