Difference between for and while loop in C, C++, Java
for loop:
for loop provides a concise way of writing the loop structure. Unlike a while loop, a for statement consumes the initialization, condition and increment/decrement in one line thereby providing a shorter, easy to debug structure of looping.
Syntax:
for (initialization condition; testing condition;
increment/decrement)
{
statement(s)
}
Flowchart:
Example:
C
#include <stdio.h> int main() { int i = 0; for (i = 5; i < 10; i++) { printf("GFG\n"); } return 0; } |
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C++
#include <iostream> using namespace std; int main() { int i = 0; for (i = 5; i < 10; i++) { cout << "GFG\n"; } return 0; } |
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Java
import java.io.*; class GFG { public static void main(String[] args) { int i = 0; for (i = 5; i < 10; i++) { System.out.println("GfG"); } } } |
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Output:
GFG GFG GFG GFG GFG
while loop:
A while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The while loop can be thought of as a repeating if statement.
Syntax :
while (boolean condition)
{
loop statements...
}
Flowchart:
Example:
C
#include <stdio.h> int main() { int i = 5; while (i < 10) { printf("GFG\n"); i++; } return 0; } |
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C++
#include <iostream> using namespace std; int main() { int i = 5; while (i < 10) { i++; cout << "GFG\n"; } return 0; } |
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Java
import java.io.*; class GFG { public static void main(String[] args) { int i = 5; while (i < 10) { i++; System.out.println("GfG"); } } } |
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Output:
GFG GFG GFG GFG GFG
Here are few differences:
| For loop | While loop |
|---|---|
| Initialization may be either in loop statement or outside the loop. | Initialization is always outside the loop. |
| Once the statement(s) is executed then after increment is done. | Increment can be done before or after the execution of the statement(s). |
| It is normally used when the number of iterations is known. | It is normally used when the number of iterations is unknown. |
| Condition is a relational expression. | Condition may be expression or non-zero value. |
| It is used when initialization and increment is simple. | It is used for complex initialization. |
| For is entry controlled loop. | While is also entry controlled loop. |
| for ( init ; condition ; iteration ) { statement(s); } |
while ( condition ) { statement(s); } |
