ABL electronic PIC12 Benutzerhandbuch

The conditional operator 

? :

is the only ternary operator in C. Syntax of the con-

ditional operator is:

expression1 ? expression2 : expression3

Expression1

evaluates first. If its value is true, then 

expression2

evaluates

and 

expression3

is ignored. If 

expression1

evaluates to false, then 

expres-

sion3

evaluates and 

expression2

is ignored. The result will be the value of

either 

expression2

or 

expression3

depending upon which evaluates. The fact

that only one of these two expressions evaluates is very important if you expect
them to produce side effects!

Conditional operator associates from right to left.

Here are a couple of practical examples:

/* Find max(a, b): */

max = (a > b) ? a : b;

/* Convert small letter to capital: */
/* (no parentheses are actually necessary) */

c = (c >= 'a' && c <= 'z') ? (c - 32) : c;

Expression1

must be a scalar expression; 

expression2

and 

expression3

must obey one of the following rules:

1. Both of arithmetic type; 

expression2

and 

expression3

are subject to the 

usual arithmetic conversions, which determines the resulting type.

2. Both of compatible struct or union types. The resulting type is the structure or 

union type of 

expression2

and 

expression3

.

3. Both of 

void

type. The resulting type is 

void

.

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