第2章Effective C

Chapter 2: Objects, Functions, Types

1. Objects, Functions, Types, and Pointers

An object is a storage in which you can represent values. More specifically speaking, it is a "region of data storage in the execution environment, and the contents of which can represent values."An object can be interpreted as having a particular type. A variable is an object.

A variable has a declared type that interprets the value of the object. The type is important as the collection of bits can be interpreted differently based on its type.
- i.e. 1 in float (IEEE754) is 0x3f800000, but if this bit pattern is interpreted as an int, it is now a different number (1,065,353,216).

A function is not an object, but it does have types. Its type is characterized by both its return type and its parameter types.

2. Declaring Variables

When we are declaring variables, we assign it a type and provide a name (identifier), by which to reference a value.

i.e. int aVariable = 5;

3. Declaring multiple variables (in a single line)

We can declare multiple variables in a single declaration(line), but it may be very confusing if the variables' types are pointers or arrays.

//one is type char* (src), and another is type char (c)
char *src, c;

//one is type int (x), one is type int[5], and one is type int[4][3] (y)
int x, y[5], z[4][3];

Exercise 2.2(関数ポインタ)

関数ポインタ配列を定義し、関数ポインタ配列から

関数を呼び出す.

関数ポインタは次のように定義されます.

//함수형 (포인터명) (함수 파라미터)
//예시:
void hello(void); //함수 프로토타입
void (*helloFuncPtr)(void); //함수 포인터

int add (int, int);
int (*addFuncPtr)(int, int);

ソリューションコードフラグメント.コードの完全版はgithubを参照してください!