Examples of conditional expressions
The following expression determines which variable has
the greater value, y or z, and assigns
the greater value to the variable x:
x = (y > z) ? y : z;
The following statement is equivalent to
the previous expression.
if (y > z)
x = y;
else
x = z;
The following expression calls the function printf,
which receives the value of the variable c, if c evaluates
to a digit. Otherwise, printf receives the character
constant 'x'.
printf(" c = %c\n", isdigit(c) ? c : 'x');
If the last operand of a conditional expression contains
an assignment operator, use parentheses to ensure the expression evaluates
properly. For example, the = operator has lower precedence
than the ?: operator in the following expression:
int i,j,k;
(i == 7) ? j ++ : k = j;
The compiler will interpret this expression as if it were
parenthesized this way:
int i,j,k;
((i == 7) ? j ++ : k) = j;
That is, k is treated as the third operand, not the entire assignment expression k = j.
To assign the value of j to k when i
== 7 is false, enclose the last operand in parentheses:
int i,j,k;
(i == 7) ? j ++ : (k = j);