Overview

Relational Operators are the type of operators used in a programming language that helps us compare any two entities, like two integers, characters, and many more. They always give the result in 1 or 0, where 1 means that the comparison is True and 0 means that the comparison is False (i.e., opposite of that).

In simple words, we can say that the output produced by the relational operators in an expression is boolean, as in boolean, there are only two values: true or false.

List of Relational Operators

Examples And Implementation of Relational Operators

As we have discussed, all the types of relational operators in C Programming language. Now let's see some examples illustrating how they can be implemented in the code.

Equality and InEquality Relational Operators

Equality and Inequality operators are opposite of each other. The equality operator returns true when both entities are equal, but the inequality operator returns true when both entities are not equal.

Here is the implementation of both equality and inequality operators in the C language.

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Less and Less than or Equal Relational Operators

The difference between less than and less than or equal operators is that the less than operator returns true only when the left operand is strictly less than the right one otherwise, it always returns false but in the case of less than or equal operator, it returns true if the left operator is less than or equal to the right operator otherwise it returns false.

Here is the implementation of both less than and less than or equal operators in C language.

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Greater than and Greater than or Equal Relational Operators

The only difference between these two of them is that the greater than operator returns true only when the left operand is strictly greater than the right one but in the case of the greater than or equal relational operator, it only returns false when the first operand is strictly less than second operand.

Here is the implementation of both greater than and greater than or equal relational operators in C language.

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Result Of A Relational Expression

All the relational operators in the C language always return boolean value which means either true or false.

Let's take an example of a relational expression, 10==9. Now here, the equals to the operator will either return a true or false value depending upon whether the expression is correct or incorrect. Similarly, every other relational operator first checks the condition and returns the required output in boolean type.

Here true means that the relation is satisfied and false means the relationship is not satisfied.

How A Program Treats True And False

The return type of all the relational operators in C language is always in the form of boolean, i.e., either true or false. So the program stores the true value as 1 and the false value as 0.

Relational Operator Precedence and Relationship With Other Operators

Precedence plays a significant role while determining the result of any expression. For example, suppose an expression consists of multiple operators. In that case, the operator with high precedence should be treated first, and the output of that operator is used to evaluate the result of the rest expression. Here is the precedence table of all operators in the decreasing order of their precedence.

Example of Precedence

As we have seen in the precedence table, let's see an example in which precedence plays an important role.

Below is the code snippet of precedence example.

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Let's see one more example of precedence.

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Comparing Characters With Relational Operators

The relational operator in C language compares all the characters according to their ASCII value.

For example, 'a' has its ASCII value of 97 and 'b' has '98', so when we compare 'a' with 'b', in general, 97 and 98 are compared.

Now let's see the code for comparing characters.

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Let us see this in the program

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Comparing Strings Or Character Array With Relational Operators

In programming languages, strings are compared from left to right using the relational operator. A relational operator in C language compares two strings character by character from left to right. The comparison is made till a match is not found or one of the strings is exhausted.

For example: If we compare the strings "abcd" and "abed". Firstly the characters at the 0th index of both strings get compared, and since both of them are equal, it moves to the next index, and when it comes to the 2nd index, it is found that the characters are distinct and output the result accordingly.

Now let's see a code implementation for comparing two strings.

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Special Case

Let's assume two strings as "abc" and "abcd". Here the first 3 characters of both the strings are equal, and the first string has no other character compared with the second string. The string with a smaller length will be treated as lexicographically small than the other one, therefore, in this case string "abc" will be less than the string "abcd".

Example:

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Character Testing Functions

There are many inbuilt Character Testing Functions in C language, predefined. First of all, to access them, we need to add a header file named #include <ctype.h>.

The return type of these character testing functions is also a boolean value (i.e., true or false);

Below is the list of all the character testing functions in C Language:

Let's see an example to understand the usage of the above functions.

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