What is the Difference Between for and while Loop?
🆚 Go to Comparative Table 🆚The main difference between a for loop and a while loop is that a for loop is used when the number of iterations is known, whereas a while loop is used when the number of iterations is unknown or must be determined during runtime. Here are some key differences between the two types of loops:
For Loop:
- Used when the number of iterations is known.
- Provides a concise way of writing the loop structure, with initialization, condition, and iteration all in one line.
- Faster than a while loop.
- Suitable for iterating through sequences like lists, arrays, or ranges when the number of elements is known.
- Example:
for (var i = 0; i < 10; i++) { /* statements */ }.
While Loop:
- Used when the number of iterations is unknown or determined during runtime.
- Allows more flexibility in determining when the loop should stop.
- Relatively slower than a for loop.
- Appropriate for situations where the loop must continue until a specific condition is met, such as iterating through a list until a certain value is found.
- Example:
while (i < 10) { /* statements */ }.
In summary, use a for loop when you know the exact number of iterations and want a concise loop structure. Use a while loop when the number of iterations is unknown or must be determined during runtime, and you need more flexibility in controlling the loop's termination condition.
Comparative Table: for vs while Loop
Here is a table comparing the differences between for and while loops:
| Feature | For Loop | While Loop |
|---|---|---|
| Syntax | for (init; condition; iteration) { statement(s); } | while (condition) { statement(s); } |
| Purpose | Used when the number of iterations is known | Used when the number of iterations is unknown |
| Initialization | Requires a specific initialization step | Does not require an initial step |
| Condition | The condition is tested before the loop body is executed | The condition is tested at the beginning of the loop |
| Termination | Terminates when the condition is no longer true | Terminates when there is no more repeat of the loop |
| Entry Control | Entry-controlled loop | Entry-controlled loop |
For loops provide a concise way of writing loop structures and are used when the number of iterations is known. On the other hand, while loops are used when the number of iterations is unknown and can be thought of as a repeating if statement.
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