Relational Operators in C Programming Language

In this tutorial, we'll explore relational operators in the C programming language. Relational operators are used to compare two values and evaluate to a boolean result (true or false). We'll cover the basic syntax and provide some examples to demonstrate their use.

Relational Operators

There are six relational operators in C:

>: greater than
<: less than
>=: greater than or equal to
<=: less than or equal to
==: equal to
!=: not equal to

Relational operators have lower precedence than arithmetic operators, so they're evaluated after any arithmetic operations in an expression. The result of a comparison using relational operators is either 0 (false) or 1 (true).

Examples

Here are some examples to demonstrate the use of relational operators in C:

#include <stdio.h>

int main() {
    int a = 5, b = 10;

    printf("a > b: %d\n", a > b);  // Output: 0 (false)
    printf("a < b: %d\n", a < b);  // Output: 1 (true)
    printf("a >= b: %d\n", a >= b); // Output: 0 (false)
    printf("a <= b: %d\n", a <= b); // Output: 1 (true)
    printf("a == b: %d\n", a == b); // Output: 0 (false)
    printf("a != b: %d\n", a != b); // Output: 1 (true)

    return 0;
}

Using Relational Operators in Conditional Statements

Relational operators are commonly used in conditional statements, like if, if-else, and switch. Here's an example that demonstrates using relational operators in if statements:

#include <stdio.h>

int main() {
    int num;

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

    if (num > 0) {
        printf("The number is positive.\n");
    } else if (num < 0) {
        printf("The number is negative.\n");
    } else {
        printf("The number is zero.\n");
    }

    return 0;
}

In this example, the user enters a number, and the program uses relational operators to determine whether it's positive, negative, or zero.

Using Relational Operators in Loops

Relational operators can also be used as loop conditions, like in for and while loops. Here's an example that demonstrates using a relational operator in a for loop:

#include <stdio.h>

int main() {
    int n, i;

    printf("Enter an integer: ");
    scanf("%d", &n);

    printf("Multiplication table for %d:\n", n);
    for (i = 1; i <= 10; i++) {
        printf("%d x %d = %d\n", n, i, n * i);
    }

    return 0;
}

In this example, the user enters an integer, and the program uses a for loop with a relational operator (i.e., i <= 10) to print the multiplication table for that integer.

Conclusion

In this tutorial, we learned about relational operators in the C programming language, their basic syntax, and usage. Relational operators are fundamental tools for making comparisons and controlling the flow of your program using conditional statements and loops.

Comparing integers and floating-point numbers using relational operators:

Description: Relational operators can be used to compare integers and floating-point numbers.

Code:

#include <stdio.h>

int main() {
    int num1 = 5;
    int num2 = 10;

    // Comparing integers
    if (num1 < num2) {
        printf("%d is less than %d\n", num1, num2);
    }

    float floatNum1 = 3.14;
    float floatNum2 = 2.5;

    // Comparing floating-point numbers
    if (floatNum1 >= floatNum2) {
        printf("%.2f is greater than or equal to %.2f\n", floatNum1, floatNum2);
    }

    return 0;
}

Chaining and combining relational operators in C programming:

Description: Relational operators can be chained or combined for more complex comparisons.

Code:

#include <stdio.h>

int main() {
    int x = 5;
    int y = 10;
    int z = 7;

    // Chaining relational operators
    if (x < y && y > z) {
        printf("%d is less than %d and %d is greater than %d\n", x, y, y, z);
    }

    // Combining relational operators
    if (x != y || y == z) {
        printf("%d is not equal to %d or %d is equal to %d\n", x, y, y, z);
    }

    return 0;
}

C code examples demonstrating the use of relational operators:

Code:

#include <stdio.h>

int main() {
    int a = 10;
    int b = 20;

    // Using relational operators in expressions
    int result = (a > b) ? a : b;
    printf("The larger value is: %d\n", result);

    return 0;
}

Boolean expressions and truth values with relational operators in C:

Description: Relational operators return Boolean values (1 for true, 0 for false), and these values can be used in boolean expressions.

Code:

#include <stdio.h>

int main() {
    int age = 25;

    // Using relational operators in a boolean expression
    int isAdult = (age >= 18);

    if (isAdult) {
        printf("You are an adult.\n");
    } else {
        printf("You are not yet an adult.\n");
    }

    return 0;
}

Common mistakes and pitfalls with relational operators in C:

Description: Common mistakes include using = instead of == for equality comparison and assuming floating-point precision for exact equality.

Code:

#include <stdio.h>

int main() {
    int x = 5;
    int y = 10;

    // Common mistake: using '=' instead of '=='
    if (x = y) {
        printf("This will always be true!\n");
    }

    float a = 0.1;
    float b = 0.1 + 0.2;

    // Common pitfall with floating-point precision
    if (a == b) {
        printf("This may not be true due to floating-point precision.\n");
    }

    return 0;
}

Relational operators in conditional statements and loops in C:

Description: Relational operators are commonly used in conditional statements (if, else if, else) and loops (while, for).

Code:

#include <stdio.h>

int main() {
    int number = 15;

    // Using relational operators in a conditional statement
    if (number > 10) {
        printf("%d is greater than 10.\n", number);
    } else {
        printf("%d is not greater than 10.\n", number);
    }

    // Using relational operators in a loop condition
    for (int i = 0; i < 5; i++) {
        printf("Iteration %d\n", i);
    }

    return 0;
}