C While Loop Examples

🔁 C `while` Loop Examples (Beginner → Advanced)

The while loop in C language is used when the number of iterations is not known in advance.
It checks the condition first, then executes the loop body.

1️⃣ Basic `while` Loop (Print 1 to 5)

Output: 1 2 3 4 5

2️⃣ `while` Loop with User Input

✔ Loop depends on user input

3️⃣ Sum of Digits Using `while` ⭐

✔ Common interview problem

4️⃣ Reverse a Number Using `while`

5️⃣ Factorial Using `while`

6️⃣ `while` Loop with Array Traversal ⭐

✔ Used when size is dynamic

7️⃣ Infinite `while` Loop ⚠️

✔ Used in:

Embedded systems
Game loops
Servers

8️⃣ `while` Loop with `break`

Output: 1 2

9️⃣ `while` Loop with `continue` ⚠️

Output: 1 2 4 5

📌 Increment before continue to avoid infinite loop

🔟 Menu-Driven Program Using `while` ⭐

✔ Very common in real programs

1️⃣1️⃣ `while` vs `for` Loop

Feature	`while`	`for`
Use case	Unknown iterations	Known iterations
Condition	Checked first	Checked first
Initialization	Outside loop	Inside loop

1️⃣2️⃣ Common Mistakes ❌

❌ Forgetting to update loop variable
❌ Infinite loop due to wrong condition
❌ Misusing continue
❌ Not initializing variable

📌 Interview Questions (Must Prepare)

Difference between while and do-while
When to use while loop?
Can while loop be infinite?
while(1) vs for(;;)
Effect of break and continue in while

✅ Summary

✔ while loop is condition-driven
✔ Best when iterations are unknown
✔ Used in menus, input validation, embedded loops
✔ Essential for logic building & interviews

C While Loop Examples