01 Intro

Basics¶

Digital data is in binary form.

• 0/1 (bit)
• 8 bits = 1 byte
• 1024 bytes = 1KB

When write a C program to perform a task, it gets converted into binary instructions which a computer can understand

Variables¶

int x; // declaration
x=5; // initialization

int x = 5; // combined

Tokens¶

• atomic unit of a code

• Key words

  return
    void
  

• Identifiers

  int x = 3;
  

Code Block¶

group of code within { ... }

Structure¶

print("hi")
print("hello")

#include <stdio.h>

void print_on_screen()
{
  printf("hi"); // ; = terminator
}

int main() // driver function of your program
{
  // code
  print_on_screen();

  int x = 4; // 

  return 0;
}

Data Types¶

Primitive¶

User-defined¶

(not in scope of current exam)

Math Operators¶

• int/int = int

• B

• ^
• Multiplication/Division (whichever comes first)
• Addition/Subtraction (whichever comes first)

Type Casting¶

change in data type of a variable for a momentary purpose

implicit (automatic)

int/int \(\to\) int

• 3/2 = 1.5
• 3/2 = 1

int/float \(\to\) float

• larger data type

int x=5;
float z = 5/(double) 5;

explicit(user-defined) type casting

int x = -5;
int y = 2;

-5/2; // -2.5 -2
5/-2; // -2.5 -2

5/-2.0f // -2.5

Relational Operators¶

• \(=\) and \(==\)
  • assignment
  • equality operator

const float pi = 3.14;

Logical Operators¶

int main()
{
  int x;

  // take input from user
  scanf("%d", &x); // storing the value in the address of x

  printf("%d", x);


  return 0;
}

// x = 5

int main()
{
  int x = 5;

  printf("%d", ++x); // 6
  printf("%d", x); // 6

  return 0;
}

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