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This article is about how to use question mark expressions in C language. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Question mark expression in C language

Question mark expression

(expression 1)? (expression 2): (expression 3)

Execute expression 2 if expression 1 is valid, otherwise execute expression 3

Give an example

Inta=5,b=3

Printf ("% d", a > btincaVlb)

Run

Execute if an is greater than b: the preceding one outputs a. Otherwise execute: the output b is followed by. In this case, the output is 5.

Points for attention

The question mark expression runs from right to left

For example

Inta=8,b=3,c=7

Printf ("d", a > Bevera > c?a:c:b > c?b:c)

It can be done in three steps.

Step 1: B > c?b:c result is c

Step 2: a > c?a:c result is a

Step 3: the results of the first two steps correspond to expression 3 and expression 2, namely a > b?a:c

The final output is an or 8

Question mark expression and comma expression

Question mark expression:

# include

Voidmain ()

{

Inta,b,c,d,e

Cedar 9

Dumb8

Scanf ("% djas% d", & a djm% d)

E = (a > b)? CRAV d

Printf ("% d\ n", e)

}

It can be understood that the whole expression after "=" can be regarded as (expression 1). If a > b, then eDec, otherwise eDead. (expression 2): (expression 3)

Comma expression:

# include

Voidmain ()

{

Inta,b,c,d,e

Cedar 9

Dumb8

Scanf ("% djas% d", & a djm% d)

E = ((a=b+c), aqd)

Printf ("% d\ n", e)

}

Make a small change based on the question mark expression to get:

The comma expression has the lowest precedence, e = ((a=b+c), aqd) first evaluates the bdistribuc assignment to a, and then evaluates the ACDD assignment to e; this is the simplest comma expression, and you can continue to add "," after ACDD.

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