> ## Documentation Index
> Fetch the complete documentation index at: https://learn.acadlink.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Operators

> All operator types in C with examples and practice problems

# Operators in C

An **operator** is a symbol that tells the compiler to perform a specific operation on one or more **operands** (variables or values).

```c theme={null}
int sum = a + b;
// '+' is the operator; a and b are operands
```

***

## Arithmetic Operators

Used to perform mathematical operations (assume `a = 10`, `b = 3`):

| Operator | Name           | Example | Result |
| -------- | -------------- | ------- | ------ |
| `+`      | Addition       | `a + b` | `13`   |
| `-`      | Subtraction    | `a - b` | `7`    |
| `*`      | Multiplication | `a * b` | `30`   |
| `/`      | Division       | `a / b` | `3`    |
| `%`      | Modulus        | `a % b` | `1`    |

`/` performs **integer division** when both operands are integers (drops the decimal). `%` gives the **remainder** of that division.

***

## Assignment Operators

Assign values to variables. The right-hand side is evaluated first, then assigned to the left.

```c theme={null}
int a = 10;           // simple assignment
int result = a + b;   // expression assigned to result
```

**Chained assignment:**

```c theme={null}
int a, b;
a = b = 20;   // b gets 20, then a gets b (both become 20)
```

**Compound assignment:**

```c theme={null}
a += 5;   // a = a + 5
a -= 3;   // a = a - 3
a *= 2;   // a = a * 2
a /= 4;   // a = a / 4
a %= 3;   // a = a % 3
```

***

## Relational Operators

Compare two values. Result is `1` (true) or `0` (false). Assume `a = 10`, `b = 5`:

| Operator | Description      | Example  | Result |
| -------- | ---------------- | -------- | ------ |
| `==`     | Equal to         | `a == b` | `0`    |
| `!=`     | Not equal to     | `a != b` | `1`    |
| `>`      | Greater than     | `a > b`  | `1`    |
| `<`      | Less than        | `a < b`  | `0`    |
| `>=`     | Greater or equal | `a >= b` | `1`    |
| `<=`     | Less or equal    | `a <= b` | `0`    |

***

## Logical Operators

Combine multiple conditions:

| Operator | Name        | Meaning                |
| -------- | ----------- | ---------------------- |
| `&&`     | Logical AND | True if both are true  |
| `\|\|`   | Logical OR  | True if either is true |
| `!`      | Logical NOT | Inverts the condition  |

```c theme={null}
int age = 20, hasLicense = 1;
if (age >= 18 && hasLicense == 1)
    printf("Eligible to drive");
```

***

## Bitwise Operators

Operate at the binary (bit) level:

| Operator | Name        | Description          |
| -------- | ----------- | -------------------- |
| `&`      | AND         | 1 if both bits are 1 |
| `\|`     | OR          | 1 if either bit is 1 |
| `^`      | XOR         | 1 if bits differ     |
| `~`      | NOT         | Flips all bits       |
| `<<`     | Left Shift  | Shifts bits left     |
| `>>`     | Right Shift | Shifts bits right    |

**Example:**

```c theme={null}
int a = 12;   // binary: 01100
int b = 25;   // binary: 11001

printf("%d", a & b);   // 01000 = 8
printf("%d", a | b);   // 11101 = 29
printf("%d", a ^ b);   // 10101 = 21
printf("%d", a << 1);  // 11000 = 24 (shift left by 1)
printf("%d", a >> 1);  // 00110 = 6  (shift right by 1)
```

***

## Increment / Decrement Operators

| Operator | Type           | Effect                    |
| -------- | -------------- | ------------------------- |
| `++a`    | Pre-increment  | Increment first, then use |
| `a++`    | Post-increment | Use first, then increment |
| `--a`    | Pre-decrement  | Decrement first, then use |
| `a--`    | Post-decrement | Use first, then decrement |

```c theme={null}
int a = 5;
printf("%d", ++a);  // prints 6 (increments before print)
printf("%d", a++);  // prints 6 (prints then increments to 7)
printf("%d", a);    // prints 7
```

***

## Practice Programs

**Problem 1: Sum, Difference, Product, Quotient, Remainder**

```c theme={null}
#include <stdio.h>
int main() {
    int a, b;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);
    printf("Sum       = %d\n", a + b);
    printf("Difference= %d\n", a - b);
    printf("Product   = %d\n", a * b);
    printf("Quotient  = %d\n", a / b);
    printf("Remainder = %d\n", a % b);
    return 0;
}
```

**Problem 2: Average of Three Numbers**

```c theme={null}
#include <stdio.h>
int main() {
    float a, b, c;
    printf("Enter three numbers: ");
    scanf("%f %f %f", &a, &b, &c);
    float avg = (a + b + c) / 3;
    printf("Average = %.2f", avg);
    return 0;
}
```

**Problem 3: Convert Days into Years, Weeks, Days**

```c theme={null}
#include <stdio.h>
int main() {
    int days, years, weeks, remaining;
    printf("Enter total days: ");
    scanf("%d", &days);
    years     = days / 365;
    weeks     = (days % 365) / 7;
    remaining = (days % 365) % 7;
    printf("Years: %d, Weeks: %d, Days: %d", years, weeks, remaining);
    return 0;
}
```

**Problem 4: Check Even or Odd**

```c theme={null}
#include <stdio.h>
int main() {
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    if (num % 2 == 0)
        printf("Even");
    else
        printf("Odd");
    return 0;
}
```

**Problem 5: Simple Interest Calculator**

```c theme={null}
#include <stdio.h>
int main() {
    float p, r, t, si;
    printf("Enter Principal, Rate, Time: ");
    scanf("%f %f %f", &p, &r, &t);
    si = (p * r * t) / 100;
    printf("Simple Interest = %.2f", si);
    return 0;
}
```