# Loops in C

Looping in C is a fundamental concept that allows you to execute a block of code repeatedly. There are three primary types of loops in C:

1. **for loop**
    
2. **while loop**
    
3. **do-while loop**
    

Each type of loop can be used depending on the specific requirement of the situation.

### 1\. for loop

The `for` loop is used when the number of iterations is known before entering the loop. The syntax is:

```c
for (initialization; condition; increment) {
    // code to be executed
}
```

**Sample Code:**

```c
#include <stdio.h>

int main() {
    int i;
    for (i = 0; i < 5; i++) {
        printf("%d ", i);
    }
    return 0;
}
```

This will output: `0 1 2 3 4`

### 2\. while loop

The `while` loop is used when the number of iterations is not known and depends on a condition. The loop will continue as long as the condition is true.

```c
while (condition) {
    // code to be executed
}
```

**Sample Code:**

```c
#include <stdio.h>

int main() {
    int i = 0;
    while (i < 5) {
        printf("%d ", i);
        i++;
    }
    return 0;
}
```

This will output: `0 1 2 3 4`

### 3\. do-while loop

The `do-while` loop is similar to the `while` loop, but the code block will execute at least once because the condition is evaluated after the block is executed.

```c
do {
    // code to be executed
} while (condition);
```

**Sample Code:**

```c
#include <stdio.h>

int main() {
    int i = 0;
    do {
        printf("%d ", i);
        i++;
    } while (i < 5);
    return 0;
}
```

This will output: `0 1 2 3 4`

### Nested Loops

Loops can be nested within other loops to perform multi-dimensional iteration.

**Sample Code:**

```c
#include <stdio.h>

int main() {
    int i, j;
    for (i = 0; i < 3; i++) {
        for (j = 0; j < 3; j++) {
            printf("(%d, %d) ", i, j);
        }
        printf("\n");
    }
    return 0;
}
```

This will output a 3x3 grid of coordinates:

```plaintext
(0, 0) (0, 1) (0, 2) 
(1, 0) (1, 1) (1, 2) 
(2, 0) (2, 1) (2, 2)
```

### Infinite Loops

An infinite loop occurs when the terminating condition will never be false. These are often used deliberately to keep a program running until an external event occurs.

**Sample Code:**

```c
#include <stdio.h>

int main() {
    while (1) {
        // This code will run forever
    }
    return 0;
}
```

### Loop Control Statements

* `break;` - Terminates the loop or switch statement and transfers execution to the statement immediately following the loop or switch.
    
* `continue;` - Causes the loop to skip the remainder of its body and immediately retest its condition prior to reiterating.
    

**Sample Code with** `break` and `continue`:

```c
#include <stdio.h>

int main() {
    int i;
    for (i = 0; i < 10; i++) {
        if (i == 5) {
            break; // Exit the loop when i is 5
        }
        if (i % 2 == 0) {
            continue; // Skip the rest of the loop body for even numbers
        }
        printf("%d ", i);
    }
    return 0;
}
```

This will output: `1 3`

Loops are a powerful feature in C that allow for efficient repetition of code blocks. They are used in almost every non-trivial program to perform tasks repeatedly.