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Difference between for and do-while loop in C, C++, Java

  • Difficulty Level : Basic
  • Last Updated : 27 Jun, 2019

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;
}

C++




#include <iostream>
using namespace std;
  
int main()
{
  
    int i = 0;
  
    for (i = 5; i < 10; i++) {
        cout << "GFG\n";
    }
  
    return 0;
}

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");
        }
    }
}
Output:
GFG
GFG
GFG
GFG
GFG

do-while loop:

do while loop is similar to while loop with the only difference that it checks for the condition after executing the statements, and therefore is an example of Exit Control Loop.

Syntax:

do
{
    statements..
}
while (condition);

Flowchart:
do-while

Example:

C




#include <stdio.h>
  
int main()
{
  
    int i = 5;
  
    do {
        printf("GFG\n");
        i++;
    } while (i < 10);
  
    return 0;
}

C++




#include <iostream>
using namespace std;
  
int main()
{
  
    int i = 5;
  
    do {
        i++;
        cout << "GFG\n";
    } while (i < 10);
  
    return 0;
}

Java




import java.io.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        int i = 5;
  
        do {
            i++;
            System.out.println("GfG");
        } while (i < 10);
    }
}
Output:
GFG
GFG
GFG
GFG
GFG

Here is the difference table:

For loopDo-While loop
Statement(s) is executed once the condition is checked.Condition is checked after the statement(s) is executed.
It might be that statement(s) gets executed zero times.Statement(s) is executed at least once.
For the single statement, bracket is not compulsory.Brackets are always compulsory.
Initialization may be outside or in condition box.Initialization may be outside or within the loop.
for loop is entry controlled loop.do-while is exit controlled loop.
for ( init ; condition ; iteration )
{ statement (s); }
do { statement(s); }
while (condition);

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