C Basics #003: while, do-while e for em linguagem C (2021)

Introduction

In this tutorial, we'll explore the different types of loops in the C programming language: while, do-while, and for. Understanding these loops is essential for controlling the flow of your program and performing repetitive tasks efficiently. By the end of this guide, you'll have a solid grasp of when and how to use each loop type.

Step 1: Understanding the while Loop

The while loop repeatedly executes a block of code as long as a specified condition is true.

Syntax

while (condition) {
    // code to be executed
}

Practical Advice

• Ensure the condition will eventually become false; otherwise, you'll create an infinite loop.
• Use the while loop when the number of iterations is not known beforehand.

Example

int i = 0;
while (i < 5) {
    printf("%d\n", i);
    i++;
}

In this example, the loop will print numbers from 0 to 4.

Step 2: Exploring the do-while Loop

The do-while loop is similar to the while loop, but it guarantees that the code block will execute at least once before the condition is tested.

Syntax

do {
    // code to be executed
} while (condition);

Practical Advice

• Use do-while when you need to ensure that the code runs at least once, such as in user input scenarios.

Example

int i = 0;
do {
    printf("%d\n", i);
    i++;
} while (i < 5);

This will also print numbers from 0 to 4, even if the initial condition is false.

Step 3: Using the for Loop

The for loop is typically used when the number of iterations is known. It combines initialization, condition checking, and incrementing all in one line.

Syntax

for (initialization; condition; increment) {
    // code to be executed
}

Practical Advice

• Ideal for situations where you know how many times you want to iterate.
• Keep the initialization and increment simple to maintain readability.

Example

for (int i = 0; i < 5; i++) {
    printf("%d\n", i);
}

This loop will also print numbers from 0 to 4.

Conclusion

In this tutorial, we've covered the three primary types of loops in C: while, do-while, and for. Each loop has its use cases, and understanding these will help you write more efficient and readable code.

Key Takeaways

• Use while for unknown iteration counts.
• Use do-while when you need at least one execution.
• Use for when the number of iterations is predetermined.

Next Steps

Try applying these loops in small coding exercises or projects to reinforce your understanding. Check out additional resources or exercises on C programming to further enhance your skills!