C Tutorial



C Tutorial

Conditional operator in the C


The conditional operator in C programming offers a concise and efficient alternative to if-else statements in situations where there is only one statement corresponding to each condition. It evaluates an expression and executes the appropriate statement based on the result, providing a streamlined solution.

Before we dive into a deeper understanding of Conditional Operators, remember to have a basic understanding of the following -

  • Ternary Operator under C programming

  • Process of Compilation in C

  • Token of C

In this article, we will explore the syntax and functionality of the conditional operator, highlighting its advantages over the if-else condition. Additionally, we will address common questions to ensure a comprehensive understanding of this powerful construct.

Difference Between Conditional Operator in C and if-else Statement in C

Conditional Operator in C

The conditional operator (ternary operator) in C is a concise expression that evaluates a condition and returns one of two values based on the result, making it useful for assigning or performing simple actions based on a condition.

If-Else Statement in C

The if-else statement in C is a control flow structure that allows the execution of different blocks of code based on a condition. It provides more flexibility and readability, making it suitable for handling complex conditions or executing multiple statements in each branch.

Conditional programming and if-else statements in C are similar as they both involve checking a condition and executing a statement based on the result.

Even though their functions are similar, they are some notable differences - 


Conditional Operator

If-Else Statement

Programming Structure

Single statement

Block of statements

Usage for Assignments

It can be used for assignments

It cannot be used for assignments

Handling Multiple Statements

Not suitable for executing multiple statements 

Suitable for executing multiple statements

Nesting Complexity

Nested conditional operators can be complex and hard to debug

Nested if-else statements are easier to read and maintain

Examples of the Conditional operator in C

Now that we understand what a conditional operator in C is, let’s study with some examples of where it is useful - 

How can you determine if the given number is odd or even using a Conditional Operator?

#include <stdio.h>

int main() {
    int number;

    printf("Enter a number: ");
    scanf("%d", &number);

    // Using the conditional operator to check if the number is odd or even
    printf("%d is %s.\n", number, (number % 2 == 0) ? "even" : "odd");

    return 0;

In this example, the program prompts the user to enter a number. The conditional operator (number % 2 == 0) ? "even" : "odd" checks if the number is divisible by 2. If the condition is true (i.e., the number is divisible by 2), the string "even" is printed. Otherwise, if the condition is false (i.e., the number is not divisible by 2), the string "odd" is printed.

Let’s see a conditional operator example after assigning the maximum value - 

int a = 10;
int b = 20;
int max = (a > b) ? a : b; // If 'a' is greater than 'b', assign 'a' to 'max'; otherwise, assign 'b' to 'max'
// After execution, max will be 20

Let’s see a conditional operator example of calculating the absolute value - 

int x = -5;
int absValue = (x < 0) ? -x : x; // If 'x' is negative, assign its negation to 'absValue'; otherwise, assign 'x' itself
// After execution, absValue will be 5

Syntax of the Conditional Operator

The conditional operator in C has the syntax:

(condition) ? expression1 : expression2

The conditions are treated as logical, where non-zero values are considered true, and 0 is considered false. expression1 and expression2 can be statements, expressions, variables, or constants. Based on the result, the operator evaluates the expression and executes either expression1 or expression2.

Working as Conditional Operator in C

In C, the conditional operator evaluates the condition and implicitly converts the result to a boolean value. If the condition is true, expression1 is executed; otherwise, expression2 is executed. The result of the operator is the result of either expression1 or expression2. Only one of the two expressions is evaluated, while the other is ignored.

Another Version of Conditional Operator in C

The conditional operator in C also has a shorter version for assigning values to a variable. Does it follow the syntax: 

variable = condition ? value1 : value2 

The condition is evaluated, and value1 is assigned to the variable if true. If the condition is false, value 2 is assigned. This version simplifies checking a condition and assigning a value to a variable.

Three Parts of the Conditional Operator in C

The three parts of the conditional operator (ternary operator) in C are:

  • Condition:

The condition is the first part of the conditional operator. It is enclosed within parentheses ( ). It represents the expression evaluated to determine whether it is true or false. It can be any valid expression in C that results in a boolean value (true or false). 

Examples of conditions include a > b, x == y, or num % 2 == 0

  • Expression1:

Expression1 is the second part of the conditional operator. It represents the expression that is executed when the condition evaluates to true. Does it follow the ‘?’ symbol, and can it be any valid expression in C? The result of expression1 is returned if the condition is true. 

For example, max = a or result = "Even" are valid expressions for expression1.

  • Expression2:

Expression2 is the third part of the conditional operator. It represents the expression that is executed when the condition evaluates to false. It follows the ‘:’ symbol and can be any valid expression in C. The result of expression2 is returned if the condition is false. 

For example, max = b or result = "Odd" are valid expressions for expression2.

Best Practices and Tips for Using the Conditional Operator

Tips for Using the Conditional Operator

  • Mind operator precedence: Use parentheses when necessary to clarify the order of operations in conditional expressions.

  • Keep it simple and readable: Use the conditional operator for concise and straightforward conditional code, avoiding complexity.

  • Limit nesting and complexity: Minimise excessive nesting of conditional operators and favour if-else statements for larger conditions.

  • Beware of side effects: Separate expressions with side effects into individual statements to clarify and prevent unexpected behaviour.

How to avoid common mistakes when using the conditional operator?

When using the Conditional Operator, it is common for even seasoned programmers to make some small mistakes. Knowing the mistakes does not necessarily help us solve the problem. However, it helps us avoid the next time - 

Mistake 1

int number = 5;
int result = (number == 1 || 2 || 3) ? 1 : 0;

Incorrect grouping of conditions. In the example, the expression (number == 1 || 2 || 3) is incorrect because each condition should be explicitly compared to the variable number. Each condition should be written as (number == 1 || number == 2 || number == 3) to ensure the desired comparison is performed correctly.

To fix this mistake, each condition should be explicitly compared to the variable number:

int number = 5;
int result = (number == 1 || number == 2 || number == 3) ? 1 : 0;

Mistake 2

When using conditional operators in C, one common mistake is omitting parentheses to control the order of evaluation. The placement of parentheses is crucial for ensuring that expressions are evaluated as intended.

For example, consider the expression ‘TRUE || FALSE && FALSE;’. In this case, the ‘&&’ operator has higher precedence than the ‘||’ operator. Without parentheses, the expression is evaluated as ‘(TRUE || FALSE) && FALSE’. However, if the intention is to evaluate ‘TRUE || (FALSE && FALSE)’, using parentheses to group the desired expressions is necessary.

Mistake 3

When working with conditional operators, thinking like a computer and considering how they evaluate expressions based on certain rules and principles is crucial. Failing to do so can lead to errors or unexpected results in our code.

One common aspect where not thinking like a computer can cause issues is understanding the concept of truthiness and falseness in programming languages. In many languages, including C, certain values are considered truthy or falsy based on their interpretation as logical conditions.

For example, any non-zero value is considered true in C, while zero is considered false.

By being aware of these common mistakes and following best practices, programmers can avoid errors and ensure that their code uses the conditional operator functions as intended.


Conditional operators in C offer a concise and efficient alternative to if-else statements for handling simple conditional expressions. However, it is important to use them judiciously, keeping code readability in mind. By understanding operator precedence, using parentheses when necessary, and thinking like a computer, developers can avoid common mistakes and maximise the benefits of conditional operators.

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1. What are the types of conditional operator in c?

In C programming, operators are categorised as unary, binary, or ternary, depending on the number of operands they operate on.

2. What are the benefits of using the conditional operator?

The conditional operator offers the advantage of reducing code length and complexity, particularly in cases where the condition and resulting statements are simple. It can make the code more concise and readable by eliminating the need for explicit if-else blocks.

3. Is substituting the if statement with the conditional operator in C possible?

No, the conditional operator cannot directly replace the if statement because it necessitates three operands, thereby necessitating the inclusion of the else part.

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