**Course Title:** Mastering C: From Fundamentals to Advanced Programming **Section Title:** Control Structures and Functions **Topic:** Loops: for, while, do-while ## Introduction to Loops Loops are a crucial control structure in programming, allowing you to execute a block of code repeatedly for a specified number of iterations or until a certain condition is met. In this topic, we'll explore the three types of loops in C: `for`, `while`, and `do-while`. ### Why Loops? Loops are essential in programming because they enable you to: * Perform repetitive tasks efficiently * Process large datasets or arrays * Implement algorithms that require iterative calculations ### Types of Loops #### 1. for Loop The `for` loop is a pre-test loop that allows you to initialize a loop counter, set a condition, and increment the counter in a single statement. **Syntax:** ```c for (initialization; condition; increment) { // loop body } ``` **Example:** ```c for (int i = 0; i < 5; i++) { printf("%d\n", i); } ``` This code initializes the loop counter `i` to 0, sets the condition `i < 5`, and increments `i` by 1 in each iteration. The loop body prints the value of `i` in each iteration. #### 2. while Loop The `while` loop is also a pre-test loop that allows you to set a condition and execute a block of code as long as the condition is true. **Syntax:** ```c while (condition) { // loop body } ``` **Example:** ```c int i = 0; while (i < 5) { printf("%d\n", i); i++; } ``` This code sets the condition `i < 5` and executes the loop body as long as the condition is true. The loop body prints the value of `i` and increments it by 1 in each iteration. #### 3. do-while Loop The `do-while` loop is a post-test loop that allows you to execute a block of code at least once and then continue executing as long as the condition is true. **Syntax:** ```c do { // loop body } while (condition); ``` **Example:** ```c int i = 0; do { printf("%d\n", i); i++; } while (i < 5); ``` This code executes the loop body at least once and continues executing as long as the condition `i < 5` is true. The loop body prints the value of `i` and increments it by 1 in each iteration. ### Key Concepts * **Loop control variables**: Use meaningful variable names to control the loop, such as `i` or `index`. * **Loop conditions**: Set clear and precise conditions for the loop to exit or continue. * **Loop increment/decrement**: Use consistent increment/decrement operations to update the loop control variable. ### Practical Takeaways * Use `for` loops when you need to iterate over a fixed number of iterations or when you need to access array elements using an index. * Use `while` loops when you need to execute a block of code repeatedly as long as a condition is true. * Use `do-while` loops when you need to execute a block of code at least once and then continue executing as long as a condition is true. ### Additional Resources * For more information on C loops, see the [C Programming Language Tutorial by tutorialspoint](https://www.tutorialspoint.com/cprogramming/index.htm). * For a detailed explanation of loop control structures, refer to the [C Language Specification by the C Standards Committee](https://port70.net/~nsz/c/c11/c11-6.html#123). ### Discussion * Do you have any questions or need help with understanding loops in C? Please leave a comment below to discuss further. **What's Next?** In the next topic, "Creating and using functions: return types and parameters," we'll explore the fundamentals of functions in C, including function signatures, function calls, and parameter passing. Stay tuned!