# Control Flow Now we're stepping into the **control flow** of C, which is how we make decisions in our code and control the order in which statements execute. Control flow gives your program the ability to **branch**, **loop**, and **handle decisions** based on conditions. Let’s break it down into two major categories: **decision-making** and **loops**. *** #### **1. Decision-Making:** In C, decision-making statements allow you to execute a block of code only if a certain condition is true. The main decision-making structures are: * **`if` statement** * **`else` statement** * **`else if` ladder** * **`switch` statement** **a. `if` statement** The `if` statement is used to check a condition. If the condition is true, the block of code inside the `if` statement is executed. **Syntax:** ```c if (condition) { // code to execute if the condition is true } ``` **Example:** ```c int age = 20; if (age >= 18) { printf("You are an adult.\n"); } ``` * The condition `(age >= 18)` is true, so `"You are an adult."` will be printed. **b. `else` statement** The `else` block executes when the `if` condition is false. **Syntax:** ```c if (condition) { // code if condition is true } else { // code if condition is false } ``` **Example:** ```c int age = 16; if (age >= 18) { printf("You are an adult.\n"); } else { printf("You are a minor.\n"); } ``` * Since `age` is 16, the else block will execute, printing `"You are a minor."` **c. `else if` ladder** If you need multiple conditions to check, you can use `else if`. **Syntax:** ```c if (condition1) { // code if condition1 is true } else if (condition2) { // code if condition2 is true } else { // code if all conditions are false } ``` **Example:** ```c int marks = 85; if (marks >= 90) { printf("Grade: A\n"); } else if (marks >= 80) { printf("Grade: B\n"); } else if (marks >= 70) { printf("Grade: C\n"); } else { printf("Grade: D\n"); } ``` * Here, `marks` is 85, so it prints `"Grade: B"`. **d. `switch` statement** When you have multiple values to compare a single variable against, a `switch` statement can be more efficient than using multiple `if-else` statements. **Syntax:** ```c switch (variable) { case value1: // code for value1 break; case value2: // code for value2 break; default: // default code if no case matches } ``` **Example:** ```c int day = 2; switch (day) { case 1: printf("Monday\n"); break; case 2: printf("Tuesday\n"); break; case 3: printf("Wednesday\n"); break; default: printf("Other day\n"); } ``` * Since `day` is 2, it prints `"Tuesday"`. *** #### **2. Loops:** Loops allow you to execute a block of code repeatedly until a condition is met. C provides three types of loops: * **`while` loop** * **`do-while` loop** * **`for` loop** **a. `while` loop** The `while` loop repeats a block of code **as long as the condition is true**. **Syntax:** ```c while (condition) { // code to execute while the condition is true } ``` **Example:** ```c int i = 1; while (i <= 5) { printf("%d\n", i); // prints 1, 2, 3, 4, 5 i++; } ``` * The condition `i <= 5` is checked each time, and the loop stops once `i` exceeds 5. **b. `do-while` loop** The `do-while` loop is similar to `while`, but the code block is executed **at least once**, even if the condition is false, because the condition is checked **after** the loop body. **Syntax:** ```c do { // code to execute } while (condition); ``` **Example:** ```c int i = 6; do { printf("%d\n", i); // prints 6 once i++; } while (i <= 5); ``` * Here, `i` starts as 6, so the block runs once, but after that, the condition `i <= 5` is false, so the loop stops. **c. `for` loop** The `for` loop is used when you know exactly how many times you want to loop. **Syntax:** ```c for (initialization; condition; increment/decrement) { // code to execute } ``` **Example:** ```c for (int i = 1; i <= 5; i++) { printf("%d\n", i); // prints 1, 2, 3, 4, 5 } ``` * The loop runs as long as the condition `i <= 5` is true. After each iteration, `i` is incremented by 1. *** #### **3. Breaking Out of Loops** You can **control** the flow of loops using: * **`break`**: Immediately exits the loop. * **`continue`**: Skips the current iteration and moves to the next one. **a. `break` Example:** ```c for (int i = 1; i <= 5; i++) { if (i == 3) { break; // stops the loop when i equals 3 } printf("%d\n", i); // prints 1, 2 } ``` **b. `continue` Example:** ```c for (int i = 1; i <= 5; i++) { if (i == 3) { continue; // skips printing when i equals 3 } printf("%d\n", i); // prints 1, 2, 4, 5 } ``` *** #### **Control Flow Summary** | Statement | Purpose | | ---------- | ------------------------------------------- | | `if-else` | Conditional branching based on true/false | | `switch` | Multi-way branching based on variable value | | `while` | Loop as long as the condition is true | | `do-while` | Loop at least once, then repeat if true | | `for` | Loop a fixed number of times | | `break` | Exit the loop entirely | | `continue` | Skip the current iteration of the loop | *** --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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