An expression is a formula that combines operands (like variables and constants) with operators (like + or *) to produce a value. An arithmetic expression is a type of expression that results in a numeric value, such as an int or a float.

For example, price * 1.05 is an arithmetic expression. Here, price and 1.05 are operands, and * is the operator.

Arithmetic Operators in C

C provides five basic arithmetic operators for performing calculations.

Important Note on Division (/):

·         Integer Division: If both operands are integers, the result is an integer, and any fractional part is truncated (discarded). For example, 10 / 3 evaluates to 3.

·         Floating-Point Division: If at least one of the operands is a floating-point type (float or double), the result is a floating-point number. For example, 10.0 / 3 evaluates to 3.333333.

Note on Modulo (%): The modulo operator can only be used with integer types.

Types of Arithmetic Expressions

1.   Integer Expressions: An expression where all operands are integer types. The resulting value is always an integer. int x = 10, y = 5; int result = x * y; // Result is 50

2.   Floating-Point (Real) Expressions: An expression where all operands are floating-point types. The resulting value is a float or double. float a = 2.5, b = 1.5; float result = a + b; // Result is 4.0

3.   Mixed-Mode Expressions: An expression containing a mix of integer and floating-point operands. In this case, C performs implicit type conversion, promoting the "lower" type (int) to the "higher" type (float or double) before the calculation. The result is always a floating-point type. int p = 5; float q = 2.0; float result = p / q; // p is promoted to 5.0f; result is 2.5

Example Program

This program demonstrates the different operators and expression types.

C

#include <stdio.h>

int main() {

    int a = 15, b = 4;

    float x = 2.5f;

    // --- Integer Expressions ---

    printf("--- Integer Arithmetic ---\n");

    printf("Addition (a + b): %d\n", a + b);         // 15 + 4 = 19

    printf("Subtraction (a - b): %d\n", a - b);        // 15 - 4 = 11

    printf("Multiplication (a * b): %d\n", a * b);      // 15 * 4 = 60

    printf("Division (a / b): %d\n", a / b);           // 15 / 4 = 3 (truncated)

    printf("Modulo (a %% b): %d\n", a % b);             // 15 % 4 = 3 (remainder)

    // --- Mixed-Mode Expressions ---

    printf("\n--- Mixed-Mode Arithmetic ---\n");

    // 'a' is promoted to a float (15.0f) before the operation

    printf("Addition (a + x): %f\n", a + x);         // 15.0 + 2.5 = 17.5

    printf("Division (a / x): %f\n", a / x);         // 15.0 / 2.5 = 6.0

    return 0;

}

Operator precedence in C defines the order in which operators in a complex expression are evaluated. For operators with the same precedence, associativity determines the evaluation order.