Introduction to Programming in C

📘 Operators and Expressions in C

Operators and expressions form the backbone of every computation in a C program. They allow you to perform arithmetic calculations, compare values, assign data, and even manipulate bits. In this chapter, we’ll explore each type of operator with examples and tips to master them effectively.

🔹 What is an Operator?

An operator is a symbol that tells the compiler to perform a specific mathematical or logical operation. For example, + is an arithmetic operator used for addition.

🧾 Types of Operators in C

🔹 Arithmetic Operators

int a = 10, b = 3;
printf("Sum = %d\n", a + b);
printf("Product = %d\n", a * b);
printf("Division = %d\n", a / b);
printf("Remainder = %d\n", a % b);

🔹 Relational Operators

Used in conditions to compare two values.

int a = 5, b = 8;
printf("%d\n", a == b);  // 0 (false)
printf("%d\n", a < b);   // 1 (true)

🔹 Logical Operators

• && → Logical AND
• || → Logical OR
• ! → Logical NOT

int a = 1, b = 0;
printf("%d\n", a && b); // 0
printf("%d\n", a || b); // 1

🔹 Assignment and Compound Assignment

int x = 5;
x += 3; // Same as x = x + 3;
printf("%d\n", x); // 8

🔹 Increment and Decrement

int a = 10;
a++; // post-increment
++a; // pre-increment
a--; // post-decrement

🔹 Ternary Operator

int a = 10, b = 20;
int max = (a > b) ? a : b;
printf("Max is %d\n", max);

🧠 Operator Precedence

Operators are evaluated in a specific order called precedence. For example, * and / have higher precedence than + and -.

Precedence Table (High to Low):

1. Postfix: () [] -> . ++ --
2. Unary: + - ! ~ ++ --
3. Multiplicative: * / %
4. Additive: + -
5. Relational: < <= > >=
6. Equality: == !=
7. Logical AND: &&
8. Logical OR: ||
9. Assignment: = += -= *= /=
10. Comma: ,

📌 Example Program

#include <stdio.h>

int main() {
    int a = 10, b = 5;
    printf("Addition: %d\n", a + b);
    printf("Is a > b? %d\n", a > b);
    printf("Logical Check: %d\n", (a > 0) && (b < 10));
    return 0;
}

📝 Practice Problems

1. Write a program to input 2 numbers and display all arithmetic results.
2. Use relational operators to compare 3 user-given numbers and find the largest.
3. Take a number and check if it is divisible by both 3 and 5 using logical operators.
4. Use a ternary operator to determine if a user-given number is even or odd.

📚 Summary

• Operators are symbols used to perform operations on variables and values.
• C supports arithmetic, relational, logical, assignment, bitwise, and other operators.
• Operator precedence affects the order of evaluation in expressions.

✅ Coming Next

In the next chapter, we’ll study Conditional Statements in C, including if, else, else if, and switch statements — crucial for decision making.