C + + variable initialization issues

The difference between initialization and assignment

In C + +, the variable initialization and assignment operators are two completely different concepts.

Initialization is not an assignment, the meaning of initialization is to assign an initial value when creating a variable allocation storage space, and the meaning of the assignment is to erase the current value of the memory space and replace it with a new value.

List initialization in C + +

int number1 = 1

int number2 (1)

int Number3 {1}

int number4 = {1}

As a new standard for c++11, curly braces are used to initialize variables for full application, which is called List initialization (listing initialization)

List initialization features: Compiler error when initializing with list and the initial value is at risk of information loss

int Num{1}//correct

int num2{1.1}//Error

int NUM3 = 1.1//correct

Default initialization

A built-in type variable defined in the body of any function is initialized to 0, and the built-in type variable defined inside the function body will not be initialized, this value is undefined, it is an indeterminate value, using the value of an uninitialized variable is a wrong way of programming, and it is difficult to hang, It is recommended that variables be initialized when each built-in type variable is defined.

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C + + variable initialization issues