Control Flow with Loops in C Programming

Loops are control structures in C that allow a block of code to be repeated multiple times, based on a condition. They are fundamental for tasks such as iterating over arrays, performing repeated calculations, and processing user input until a condition is met.

while Loop

The while loop checks the condition before executing the loop body. If the condition is true, the statements inside the loop are executed repeatedly until the condition becomes false.

Syntax:

while (condition) statement;

• The loop may execute zero or more times depending on the condition.
• Use when the number of iterations is not known in advance.

do...while Loop

The do...while loop executes the loop body at least once, then checks the condition. If the condition is true, it continues; otherwise, it exits.

Syntax:

do statement; while (condition);

• Guarantees the loop runs at least once, even if the condition is false initially.
• Useful when you want the loop body to run before validating the condition (e.g., user input menus).

for Loop

The for loop is best when the number of iterations is known. It includes initialization, condition, and update expressions all in one line.

Syntax:

for (initialization; condition; update) statement;

• Most commonly used loop structure in C.
• Suitable for counters, indexing arrays, or repeating a block a fixed number of times.

Nested Loops

A loop inside another loop is called a nested loop. All types of loops (for, while, do...while) can be nested.

Syntax (Nested for example):

for (i = 0; i < n; i++) for (j = 0; j < m; j++) statement;

• Useful for multi-dimensional data processing (like matrices).
• The inner loop runs completely for each iteration of the outer loop.

break Statement

The break statement is used to terminate a loop immediately, skipping the remaining iterations.

Syntax:

if (condition) break;

• Commonly used in loops and switch statements to exit early.
• Helps in improving efficiency when the desired result is achieved.

continue Statement

The continue statement skips the current iteration of the loop and continues with the next iteration.

Syntax:

if (condition) continue;

• Useful when certain iterations need to be skipped based on conditions.

Summary

Mastering loops and control flow statements is essential in C programming. Loops help in reducing code duplication and automating repetitive tasks, while break and continue provide finer control over execution. Using the right loop in the right scenario improves both readability and performance of your code.