C++ function return value encyclopedia: mastering types and meanings

The return value type of the C function defines the operation result after the function is executed. Basic types include void (returns no value), bool (true or false), and numeric types (integer and floating point). Pointer types point to objects or dynamically allocated memory. Reference types provide direct access to original variables. Practical case: The maximum value calculation function returns the maximum value of two integers, and the dynamic memory allocation function returns a pointer to the allocated space.

C Complete collection of function return values: Master the types and meanings

The function return value is an important part of the function and indicates the function The result of the operation after execution. There are various return value types defined in C, each type represents a different meaning และข้อมูล type.

Basic type

• void: means the function does not return any value.

  void greet() {
  std::cout << "Hello world!" << std::endl;
  }

• Boolean type (bool): Represents true (true) or false (false).

  bool isEven(int number) {
  return (number % 2 == 0);
  }

• Numeric types: Including integer types (int, long, short) and floating point types (float, double, long double).

  int sum(int a, int b) {
  return a + b;
  }

Pointer type

• Pointer to an object or dynamically allocated memory: Storage object or allocated memory address.

  std::string* createString() {
  return new std::string("Hello");
  }

Reference type

• Reference to a variable: Provides direct access to the original variable access.

  int& getMax(int& a, int& b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
  }

Integer type

• int: Represents an integer whose size is the word length of the CPU platform.
• long: Represents an integer whose size is machine word length, usually larger than the int type.
• short: Represents an integer smaller than the int type.

Floating point type

• float: represents a single-precision floating point number, and the precision is usually 24 bits.
• double: represents a double-precision floating point number, and the precision is usually 53 bits.
• long double: represents an extended precision floating point number, and the precision is usually higher.

Practical case

Maximum value calculation:

int getMax(int a, int b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}

This function accepts two integer parameters, and Return the larger one.

Dynamic allocation of memory:

std::string* createString() {
  return new std::string("Hello");
}

This function dynamically allocates the memory space of a std::string object and returns a pointer to the space.

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