Loops in C programming allow you to repeat a block of code multiple times until a specific condition is met. They simplify complex tasks by avoiding the need to write repetitive code. There are three primary types of loops in C: do-while, while, and for. Each loop has its own use case and syntax.
• Code Reusability: Loops help you write code that can be executed multiple times without repeating the same code block.
• Efficient Coding: Loops reduce redundancy and make your code more efficient and easier to maintain.
• Data Structure Traversal: Loops are essential for traversing elements in data structures such as arrays and linked lists.
1. do while
2. while
3. for
The do-while loop executes a block of code at least once and then repeats the execution based on the condition. It is also known as a post-tested loop because the condition is tested after the code block is executed.
do {
// Code to be executed
} while (condition);
1. Execute the code block.
2. Check the condition.
3. If the condition is true, repeat the loop. If false, exit the loop.
The while loop is used when the number of iterations is not known beforehand. It is a pre-tested loop because the condition is checked before the code block is executed.
while (condition) {
// Code to be executed
}
1. Check the condition.
2. If the condition is true, execute the code block.
3. Repeat the loop until the condition becomes false.
The for loop is used when the number of iterations is known beforehand. It initializes a variable, tests a condition, and updates the variable in a single line. It is also a pre-tested loop.
for (initialization; condition; increment/decrement) {
// Code to be executed
}
1. Initialize the loop variable.
2. Check the condition.
3. If the condition is true, execute the code block.
4. Update the loop variable.
5. Repeat the loop until the condition becomes false.
| Feature | do-while Loop | while Loop | for Loop |
|---|---|---|---|
| When to Use | When you need at least one execution | When the number of iterations is unknown | When the number of iterations is known |
| Condition Test | After executing the loop block | Before executing the loop block | Before executing the loop block |
| Initialization | Not necessary (but can be included) | Not necessary (but can be included) | Required as part of the syntax |
| Loop Variable Update | Not required (but can be included) | Not required (but can be included) | Included in the syntax |
| Example Use Case | Menu-driven programs or cases where at least one execution is required | Reading data until end of file or a condition becomes false | Iterating a fixed number of times or over a range |