Loops
Introduction to C
Structure of a C Program
Variables and Data Types
Input and Output
Operators in C
Decision Making
If Statement
if...else Statement
Nested if Statement
Nested if...else Statement
Switch Statement
Loops
For Loop
While Loop
Do While Loop
Loop Comparison
Arrays
Strings
Functions
Function Types
Library Functions
User-Defined Functions
Recursion Function
Pointers
Structures
File Handling
Common Mistakes
Ideas
Loops
Control Flow: Loops in C
Loops are used to repeat a block of code multiple times. Instead of writing the same code over and over, you use a loop to automate the process, making your programs efficient and easy to maintain.
1. The for Loop
The for loop is best used when you know exactly how many times you want to repeat a block of code.
for (initialization; condition; increment/decrement) { ... }
for (int i = 1; i <= 5; i++) { printf("%d\n", i); }
2. The while Loop
The while loop repeats as long as a condition is True. It is ideal when you don't know the exact number of iterations beforehand.
int i = 1; while (i <= 5) { printf("%d\n", i); i++; // Don't forget to update the counter! }
3. The do...while Loop
Similar to the while loop, but with one key difference: the code block always runs at least once because the condition is checked after the code executes.
int i = 1; do { printf("%d\n", i); i++; } while (i <= 5);
Loop Control Statements
| Keyword | Action |
|---|---|
break |
Exits the loop immediately, even if the condition is still true. |
continue |
Skips the current iteration and jumps to the next cycle of the loop. |
Student Alert: Always ensure your loop has a way to end! If the condition never becomes false, you will create an "Infinite Loop," which can cause your program to crash or freeze.