In C programming, loops allow you to repeat a block of code multiple times. The three main types of loops are `for`, `while`, and `do-while`. Each has a specific use case depending on the structure of your code.
### 1. **For loop:**
A `for` loop is generally used when you know the number of iterations ahead of time.
```c
#include <stdio.h>
int main() {
for (int i = 0; i < 5; i++) {
printf("%d\n", i);
}
return 0;
}
```
This will print numbers from 0 to 4. Here, the loop runs 5 times, as it starts with `i = 0` and increments until `i < 5` is false.
### 2. **While loop:**
A `while` loop runs as long as the condition is true. It's more flexible than a `for` loop when the number of iterations isn’t known beforehand.
```c
#include <stdio.h>
int main() {
int i = 0;
while (i < 5) {
printf("%d\n", i);
i++;
}
return 0;
}
```
This will also print numbers from 0 to 4, but the condition is checked before each iteration.
### 3. **Do-while loop:**
A `do-while` loop ensures that the block of code runs at least once before checking the condition.
```c
#include <stdio.h>
int main() {
int i = 0;
do {
printf("%d\n", i);
i++;
} while (i < 5);
return 0;
}
```
The condition is checked after each iteration, so the code inside the loop runs at least once.
### Common Pitfalls:
- **Infinite Loops:** Ensure that your loop conditions eventually become false, or you'll run into infinite loops.
- **Off-by-One Errors:** Be careful with boundary conditions (`<`, `<=`), especially in `for` loops.