Operators

1. Operators

Operators in C are symbols that perform operations on variables and values. They are classified into several categories:

1.1. Arithmetic Operators

Used for basic arithmetic operations:

• Addition: +

  int a = 5 + 3; // a = 8

• Subtraction: -

  int a = 5 - 3; // a = 2

• Multiplication: *

  int a = 5 * 3; // a = 15

• Division: /

  int a = 6 / 3; // a = 2

• Modulus (remainder): %

  int a = 5 % 3; // a = 2

1.2. Relational Operators

Used to compare values:

• Equal to: ==

  if (a == b) // Checks if a is equal to b

• Not equal to: !=

  if (a != b) // Checks if a is not equal to b

• Greater than: >

  if (a > b) // Checks if a is greater than b

• Less than: <

  if (a < b) // Checks if a is less than b

• Greater than or equal to: >=

  if (a >= b) // Checks if a is greater than or equal to b

• Less than or equal to: <=

  if (a <= b) // Checks if a is less than or equal to b

1.3. Logical Operators

Used to perform logical operations:

• Logical AND: &&

  if (a > 0 && b > 0) // True if both conditions are true

• Logical OR: ||

  if (a > 0 || b > 0) // True if at least one condition is true

• Logical NOT: !

  if (!(a > 0)) // True if a is not greater than 0

1.4. Bitwise Operators

Operate on bits and perform bit-level operations:

• Bitwise AND: &

  int a = 5 & 3; // Result is 1 (0101 & 0011 = 0001)

• Bitwise OR: |

  int a = 5 | 3; // Result is 7 (0101 | 0011 = 0111)

• Bitwise XOR: ^

  int a = 5 ^ 3; // Result is 6 (0101 ^ 0011 = 0110)

• Bitwise NOT: ~

  int a = ~5; // Result is -6 (complement of 0101 is 1010)

• Left Shift: <<

  int a = 5 << 1; // Result is 10 (0101 << 1 = 1010)

• Right Shift: >>

  int a = 5 >> 1; // Result is 2 (0101 >> 1 = 0010)

1.5. Assignment Operators

Used to assign values to variables:

• Simple Assignment: =

  int a = 5;

• Add and Assign: +=

  a += 3; // Equivalent to a = a + 3

• Subtract and Assign: -=

  a -= 2; // Equivalent to a = a - 2

• Multiply and Assign: *=

  a *= 4; // Equivalent to a = a * 4

• Divide and Assign: /=

  a /= 2; // Equivalent to a = a / 2

• Modulus and Assign: %=

  a %= 3; // Equivalent to a = a % 3

1.6. Increment and Decrement Operators

Used to increase or decrease the value of a variable:

• Increment: ++

  int a = 5;
  a++; // Equivalent to a = a + 1

• Decrement: --

  int a = 5;
  a--; // Equivalent to a = a - 1

1.7. Conditional (Ternary) Operator

A shorthand for if-else statements:

int a = (b > 0) ? 1 : -1; // If b > 0, a = 1, else a = -1

1.8. Sizeof Operator

Used to get the size of a variable or type in bytes:

int size = sizeof(int); // Size of int in bytes

2. Instructions

Instructions in C are the basic commands that the compiler translates into machine code. Here are a few key instructions:

2.1. Assignment

int x = 10; // Assigns 10 to x

2.2. Control Flow Instructions

• if Statement

  if (condition) {
      // Code to execute if condition is true
  }

• else Statement

  if (condition) {
      // Code to execute if condition is true
  } else {
      // Code to execute if condition is false
  }

• switch Statement

  switch (expression) {
      case value1:
          // Code to execute for value1
          break;
      case value2:
          // Code to execute for value2
          break;
      default:
          // Code to execute if no case matches
  }

• while Loop

  while (condition) {
      // Code to execute while condition is true
  }

• for Loop

  for (initialization; condition; increment) {
      // Code to execute while condition is true
  }

• do-while Loop

  do {
      // Code to execute
  } while (condition); // Condition checked after execution

2.3. Function Calls

To call a function:

functionName(arguments); // Calls a function with provided arguments

2.4. Return Statement

Returns a value from a function and exits the function:

return value; // Returns value to the caller

2.5. Break and Continue

• break: Exits the current loop or switch statement

  break;

• continue: Skips the rest of the code in the current loop iteration and starts the next iteration

  continue;

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Summary

• Operators in C include arithmetic, relational, logical, bitwise, assignment, increment/decrement, conditional, and sizeof operators.

• Instructions include assignment, control flow statements (if, else, switch), loops (while, for, do-while), function calls, return, and loop control (break, continue)(We'll study more about them in Control Flow).