Operators and Overloading in C++

Access and Range Checking

• When using an operator to access, it will first check if the subscript is between 0 and 10.
• Out-of-range accesses will print "out of range" error message.
• The hardware performs the checks, so the user doesn’t need to worry.

Copy Constructor and Assignment

• The matrix class (array) has two constructors: the default constructor and the copy constructor.
• Copy constructor example: array integers3.
• Copy Constructor:
  • Assigns values at the time of declaration.
• Assignment:
  • Assigns values after declaration.
  • Example: integers1 = integers3.

Custom Operator

• operator []: can accept any data type, not just integers.
• The incoming data type must have the corresponding operation.
• Global Operator overloading like < and > cannot be implemented inside Cin and Cout.
• Implementation: can only be global functions instead of member functions.

Constructor and Destructor

• When array uses dynamic memory, ensure to release the memory in the destructor.
• Otherwise, it will only release the pointer, not the actual memory.

Constant and Reference

• Ensure the incoming data is not modified: use const and pass-by-reference.
• Importance: Prevents infinite self-call copies.

Reinforcement

• C++ provides default copy control mechanisms:
  • Even if not written, default copy control and assignment exist.
  • But when the class has dynamic memory, those functions must be implemented manually.
• Otherwise, errors may occur.

Compiler Behavior

• The compiler will help you with type casting.
• Example: static_cast<double>(int).

String Class Overloading

• The STL String class provides many string handling functions.
• Example: str1 += str2 is equivalent to str1 = str1 + str2.
• Substring extraction: str1.substring(0, 14).
• Access with range checking: use the at() method, which throws an exception.
• Non-at() methods may result in undetected errors.

Using Exception Handling

• Try-catch is commonly used in C++ libraries to handle exceptions.

Why myString = "Hello" Can Work

• The compiler first creates a temporary String object, then converts the char array to this temporary object, and finally assigns it to the target String object.

Summary

• Understand the importance of operator overloading and string handling.
• Understand default and custom constructors and assignment operations.
• Understand compiler behavior when encountering different data types.
• Learn how to handle errors and use exception handling to prevent program errors.