C: Ternary operator

Send Close Add comments: (status displays here)

Got it! This site uses cookies. You consent to this by clicking on "Got it!" or by continuing to use this website.nbsp; Note: This appears on each machine/browser from which this site is accessed.

C: Ternary operator

by RS admin@ycp.powersoftwo.org

1. C: Ternary operator

Some expressions involve unary operators such as arithmetic negation or logical negation.

Some expressions involve binary operators such as arithmetic addition, subtraction,e etc., or logical conjunction, disjunction, etc.

There is a common ternary operator "?" (question mark) that takes three operands. It is sometimes called a conditional expression (as contrasted with the "if then else") conditional control flow statement. Here is the C code.

#include <stdio.h>

int main() {
	// declarations
	int x1;
	int x2;
	// input
	scanf("%d",&x1);
	// process
	if (x1 < 0) {
		x2 = - x1;
		}
	else {
		x2 = x1;
		}
	// output
	printf("The absolute value of %d is %d.\n",x1,x2);
	return 0;
	}

2. Examples of input and output

Here are some examples of input and output for the above program code.

Here is an example input.

-1

For the above example input, here is the expected output.

The absolute value of -1 is 1.

Here is an example input.

1

For the above example input, here is the expected output.

The absolute value of 1 is 1.

Here is an example input.

0

For the above example input, here is the expected output.

The absolute value of 0 is 0.

Here is the C code.

#include <stdio.h>

int main() {
	// declarations
	int x1;
	int x2;
	// input
	scanf("%d",&x1);
	// process
	x2 = (x1 < 0) ? - x1 : x1;
	// output
	printf("The absolute value of %d is %d.\n",x1,x2);
	return 0;
	}

3. Examples of input and output

Here are some examples of input and output for the above program code.

Here is an example input.

-1

For the above example input, here is the expected output.

The absolute value of -1 is 1.

Here is an example input.

1

For the above example input, here is the expected output.

The absolute value of 1 is 1.

Here is an example input.

0

For the above example input, here is the expected output.

The absolute value of 0 is 0.

4. If-then-else expression

The ternary expression, or if-then-else expression, has the following general form.

condition ? then-expression : else-expression

Both then-expression and else-expression are required.

I prefer to usually use parentheses around the condition part of the conditional expression.

5. If-then-else statement

By contrast, the if-then-else statement has the following form.

if (condition) { then-statements } else { else-statements }

The else-statements (and else-part) can be omitted if not needed. Note: In the above example programs, the use of the ternary operator takes 5 lines (in the if-then-else statement) to one line (using the if-then-else expression).

6. End of page

7. Multiple choice questions for this page

1

by RS admin@ycp.powersoftwo.org