How to set priorities in C language? Elaborate on C language priorities

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

0. Why should we master priorities

Think about these two questions ：

a. Read someone else's code , I can't understand the priority problem , What do I do ？

b. A bunch of parentheses , Is it beautiful ？

I wanted to decorate the wall with a picture , But a pile of paper was used to fix ！

Some people say that the code is written too much , Of course . This is a very broad statement . Look at the level of the code you write , Some things you may have been

Can't touch , What about proficiency . Some things must be combed , summary .

1. priority

1.1 Priority chart

The operator with the highest priority is not a real operator , Include ： The array subscript , Function call , Structure member selector .

Monocular operators take second place .(! ~ ++ — – (type) * & sizeof)

Then there is binocular operator . In the binocular operator , Arithmetic operator (* / % + -) The highest priority , displacement (<< >>) second , Relationship

Operator (< <= > >= != ==) third , Then there is the bitwise operator (& ^ | ), Logical operators (&& ||) Conditional operator (?: Three orders ),

Assignment operator (= …).

Any logical operator has a lower priority than any relational operator .

The shift operator has a lower priority than the arithmetic operator , But higher than relational operators .

1.2 Operator instance

a. while (c = getc(in) != EOF)

putc(c, out)

Loop means copying one file to another . But because of != The priority of is higher than that of the assignment operator , therefore c

Given to getc() The return value of is the same as EOF Boolean value after comparison , The result is to out A pile of 1.

1.3 Priority doggerel

Vinegar jar sour filling

The taste falls and the blessing beans jump

common 44 Operators

vinegar － Elementary ,4 individual ： ( ) [ ] -> Point to structural members . Structural members

The altar － Monocular ,9 individual ： ! ~ ++ — - Minus sign ( type ) * The pointer & Address fetch sizeof length

acid － The arithmetic ,5 individual ： * / % + - reduce

taste － Displacement ,2 individual ： << >>

irrigation － Relationship ,6 individual ： < <= > >= == be equal to != It's not equal to

taste － Bit logic ,3 individual ： & Bitwise AND ^ Bitwise XOR | Press bit or

fall － Logic ,2 individual ： && Logic and || Logic or

jump － Conditions ,1 individual , Three orders ： ? :

blessing － assignment ,11 individual ： = += -= *= /= %= >>= <<= &= ^= |=

bean － comma ,1 individual ： ,

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