chtp02

Introduction to C Programming

Objectives

Write simple programs in C.
Use simple input/output statements.
Understand fundamental data types.
Learn computer memory concepts.
Use arithmetic operators and learn their precedence.
Write simple decision-making statements.

Program Structure

Basic Components of a C Program

Comments: Labeled with // for single-line or /*...*/ for multi-line; improve code readability without affecting execution.
Preprocessor Directive: #include <stdio.h> includes standard input/output functions such as printf.
Main Function: int main(void) is where C programs begin execution. It returns an integer value.

Printing Output

Printing a Simple Message: Using printf to display text.
- Example: printf("Welcome to C!\n");
- \n is an escape sequence for newline.

Basic Input and Output

Variables and Data Types

Variable Definition: Every variable must be defined with a type before use. Example: int integer1, integer2;
Types: int for integers.

Input Using `scanf`

Example: scanf("%d", &integer1); reads an integer input by the user.
Address Operator: & indicates the memory location where the data should be stored.

Arithmetic Operators

C uses operators like +, -, *, / for operations. The remainder operator % finds out division remainders, e.g., 7 % 4 results in 3.
Integer Division: E.g., 7 / 4 yields 1.

Operator Precedence

Parentheses ()
Multiplication *, Division /, Remainder %
Addition +, Subtraction -
Assignment =

Decision Making in C

If Statement: Executes a block of code based on a condition.
- Syntax: if (condition) { /* statements */ }
- Example: Checks equality with operators: ==, !=, <, >, <=, >=.

Programming Best Practices

Indentation and Comments: Enhance code readability. Every function should have a comment describing its purpose.
Variable Naming: Use meaningful names for clarity.
Avoid Confusing Operators: Distinguish between the assignment operator = and equality operator ==.