## Chapter 5: Control Structures **What is a Control Structure?** We use control structures when a program needs to make decisions or perform actions based on conditions. In simple words: "If this happens, do this, otherwise do something else." ### 1. If-Else Statement **What does an if statement do?** * It checks a condition. * If the condition is true -> the code inside will execute. * If it is false -> the code will be skipped. **Real-life example** * If age >= 18 -> Adult * If age < 18 -> Minor ```c #include int main() { int userAge; printf("Enter your age: "); scanf("%d", &userAge); if (userAge >= 18) { printf("You are an adult.n"); } return 0; } ``` If-Else: **What is if-else?** * if -> when the condition is true * else -> when the condition is false ```c if (userAge >= 18) { printf("You can vote.n"); } else { printf("You cannot vote yet.n"); } ``` If-Else-If Ladder: **What is an if-else if ladder?** When multiple conditions need to be checked and only one condition should be true, we use an if-else if ladder. The flow goes from top to bottom. The first condition that is true is executed. All others are skipped. ```c #include int main() { int score; printf("Enter your score: "); scanf("%d", &score); if (score >= 90) { printf("Result: A+n"); } else if (score >= 80) { printf("Result: An"); } else if (score >= 70) { printf("Result: Bn"); } else if (score >= 60) { printf("Result: Cn"); } else if (score >= 50) { printf("Result: Dn"); } else { printf("Result: Fn"); } return 0; } ``` ### 2. Switch Statement **What is a Switch Statement?** A switch statement is used when there are fixed options for a single variable (like 1-7, menu choices, day number, option number). It's a cleaner and easier version of if-else statements. Comparison is only done using equality (==). ```c #include int main() { int choice; printf("Enter day number (1-7): "); scanf("%d", &choice); switch (choice) { case 1: printf("Mondayn"); break; case 2: printf("Tuesdayn"); break; case 3: printf("Wednesdayn"); break; case 4: printf("Thursdayn"); break; case 5: printf("Fridayn"); break; case 6: printf("Saturdayn"); break; case 7: printf("Sundayn"); break; default: printf("Invalid choice!n"); } return 0; } ``` Important: The break statement is very important! Without it, the execution "falls through" to the next case. ### 3. Loops **What are Loops?** Loops are used to repeat the same task multiple times as long as the condition is true. Examples: * Counting from 1 to 5 * Printing a message 10 times * Calculating the sum of numbers While Loop ** When to use a while loop? When the condition is known beforehand, but the exact number of iterations is not certain. ```c #include int main() { int number = 1; while (number <= 5) { printf("Count: %dn", number); number++; } return 0; } ``` **Output:** ``` Number: 1 Number: 2 Number: 3 Number: 4 Number: 5 ``` Do-While Loop **What is a do-while loop?** * A do-while loop executes at least once. * The code runs first, * then the condition is checked. Therefore, even if the input is incorrect, there is still a chance to get input at least once. ```c #include int main() { int inputvalue; do { printf("Enter a positive number: "); scanf("%d", &inputvalue); if (inputvalue <= 0) { printf("This is not positive! Try again.n"); } } while (inputvalue <= 0); printf("Thank you! You entered: %dn", inputvalue); return 0; } ``` For Loop **What is a for loop?** * A for loop is used when we know beforehand how many times the loop needs to run. * In this example, the loop will run 10 times. * Each time the value from 1 to 10 will be printed. ```c #include int main() { // Print numbers from 1 to 10 for (int num = 1; num <= 10; num++) { printf("%d ", num); } printf("n"); return 0; } ``` Description of For Loop: ```c for (initialization; condition; increment) { // Code to repeat } ``` * A for loop is used when... This happens when we know how many times the task needs to be repeated. * Each time, the next multiplication of the table is printed. Multiplication Table Example: ```c #include int main() { int value; printf("Enter a number: "); scanf("%d", &value); printf("Multiplication table for %d:n", value); for (int count = 1; count <= 10; count++) { printf("%d x %d = %dn", value, count, value * count); } return 0; } ``` ### 4. Loop Control Statements Break - Exits the loop immediately: ```c for (int i = 1; i <= 10; i++) { if (i == 5) { break; // Stops when i is 5 } printf("%d ", i); } // Output: 1 2 3 4 ``` Continue - Skips the current iteration: ```c for (int i = 1; i <= 5; i++) { if (i == 3) { continue; // Skips 3 } printf("%d ", i); } // Output: 1 2 4 5 ``` --- ## Conclusion In this article, we explored the core concepts of Explore blog under C language - Control Structures. Understanding these fundamentals is crucial for any developer looking to master this topic. ## Frequently Asked Questions (FAQs) **Q: What is Explore blog under C language - Control Structures?** A: Explore blog under C language - Control Structures is a fundamental concept in this programming language/topic that allows developers to perform specific tasks efficiently. **Q: Why is Explore blog under C language - Control Structures important?** A: It helps in organizing code, improving performance, and implementing complex logic in a structured way. **Q: How to get started with Explore blog under C language - Control Structures?** A: You can start by practicing the basic syntax and examples provided in this tutorial. **Q: Are there any prerequisites for Explore blog under C language - Control Structures?** A: Basic knowledge of programming logic and syntax is recommended. **Q: Can Explore blog under C language - Control Structures be used in real-world projects?** A: Yes, it is widely used in enterprise-level applications and software development. **Q: Where can I find more examples of Explore blog under C language - Control Structures?** A: You can check our blog section for more advanced tutorials and use cases. **Q: Is Explore blog under C language - Control Structures suitable for beginners?** A: Yes, our guide is designed to be beginner-friendly with clear explanations. **Q: How does Explore blog under C language - Control Structures improve code quality?** A: By providing a standardized way to handle logic, it makes code more readable and maintainable. **Q: What are common mistakes when using Explore blog under C language - Control Structures?** A: Common mistakes include incorrect syntax usage and not following best practices, which we've covered here. **Q: Does this tutorial cover advanced Explore blog under C language - Control Structures?** A: This article covers the essentials; stay tuned for our advanced series on this topic.