Difference between while and for loop c programming Language.

Given Diagram shows how for and while loop works.
for Loop:
1. Initializer: The initialization expression is executed, which is used to declare and initialize counter variables.
2. The Condition: The expression condition is tested returns true or false. If the expression is true, continue with step 3. Otherwise, the loop is finished.
3.The statements inside the body is executed.
4.Iterator: iterator the update expression (++,--) is executed, which increases or decreases the counter variable value i by 1.
5. Continue to the Back to Step 2.
Steps 2–5 are repeated as long as the condition is true.

Difference between while loop vs for loop:

1. While loop:

i.Initialization is always outside the loop.
ii.The condition may be an expression or non-zero value.
iii. It is normally used when the number of iterations is unknown.
iv.The increment can be done before or after the execution of the statement(s).
v.While loop is also entry controlled loop.
vi. It is used for complex initialization.
vii. Syntax:
while ( condition )
{
statement(s);
}

2. for loop:

i.Initialization may be either in the loop statement or outside the loop.
ii.Condition is a relational expression.
iii. It is normally used when the number of iterations is known.
iv.Once the statement(s) is executed then increment is done.
v. For loop is entry controlled loop.
vi. It is used when initialization and updation of conditions are simple.
vii. Syntax:
for ( init ; condition ; iteration )
{
statement(s);
}

C program to illustrate use for loop

/* C program given below demonstrate the for loop */
#include <stdio.h>
int main()
{
int i;
for (i = 0; i < 10; i++)
{
printf("\n%d, ", i);
}
return 0;
}

Output:
0 1 2 3 4 5 6 7 8 9 
Explanation : The program above displays the numbers from 0 to 9.
Step 1: int i;
The variable i is declared as integer to store integer numbers.
Step 2: The control enters into the for loop.
for (i = 0; i < 10; i++)
{
printf("\n%d, ", i);
}
  2.1 : intilize the variable i to 0 in intilization section of for loop. .i.e i=0
  2.2 : control jumps to test the condition in the condition section , i<10 the condition tested is true i.e. 0<10 results in true, and executes the printf("%d, ",i);
display the output 0
Step 3: The process repeates till the value of i<10, And as soon as the value of i becomes 10, then execution of the loop terminates and stops the execution.
And finally shows the final output.



C program to illustrate use of while loop

/* C program given below demonstrate the use of while loop */
#include <stdio.h>
int main()
{
int count = 0;
while (count <10)
{
printf("%d ", count);
count++;
}
return 0;
}

Output:
0 1 2 3 4 5 6 7 8 9 
The program above displays number in order between range 0 to 9

Explanation : i. int count = 0;
The variable counter count is declared as int variable and assigned value 0. i.e count=0.
ii. control enters in to the while loop.
while (count <10)
tests the condition expression which is true (while(0<10)) then control enters into the while loop body.
iii. And executes
printf("%d ", count);
count++;
displays the value of count i.e.  0 on the output screen and increment(count++) the value of count by 1 then count becomes 1 , count=1.
This process continues till the value of count<10.
when the value of count becomes 10 (count=10)then
the condition while(count<10) becomes false and stop the execution of the loop.


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