C language left value and right value description [easy to understand]

Hello everyone , I meet you again , I'm your friend, Quan Jun .

The left value ： The name or expression used to calibrate a specific data object .

there Data objects Refers to the data storage area . And C++ There are differences between the objects facing the objects .

therefore , An lvalue refers to an address in memory .

But some variables cannot modify the value in memory , Like using const Variables created by qualifiers . To distinguish from these variables , The modifiable object is called Modifiable lvalue .

So the assignment operator = The left side of should be a modifiable lvalue .

Right value ： The quantity that can be assigned to the modifiable lvalue . The right value cannot be the left value itself . The right value can be a constant 、 Variable 、 Expression or function return value, etc .

for example

year = 2020;

Copy

here year Is a modifiable lvalue , and 2020 Is a modifiable right value .

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