For Loop

The wizards of For Loop A Lecture By Abdul Ghaffar Khan

‘ C’ and Iterative Logic
To apply the Iterative logic we have three control structures in ‘C’ Language as listed below,
for Loop
while loop
do while loop
Ch – 8 For Loop By Abdul Ghaffar Khan

The for Loop:
for loop is used when a process is to repeat a fixed number of times. The structure of a for loop is as follows
for(expression_l; expression_2; expression_3)
any_instruction;
Or
for(expression_l; expression_2; expression_3)
{
body-of-IOOP
}

Order of execution
When the loop is started normally a control variable is initialized by executing expression_l.
expression_2 is tested if it is false then control is transferred outside the loop otherwise do next step 3
Body of loop is executed.
Value of control variable is altered by expression_3
Steps (2) to (4) are repeated until condition becomes false
for(exl; ex2; ex3)
{
body-of-IOOP
}

Example 8.1 ( Print 10 natural numbers) Ch – 8 For Loop By Abdul Ghaffar Khan main() { int NBR; clrscr(); for(NBR=l; NBR<=10; ++NBR) printf("%d ",NBR); getch() } Output: 2 3 4 5 6 7 8 9 10

Example 8.2 ( print a table )
main()
{
int n, p, i= 0;
clrscr();
printf("Enter a number whose table is to print ");
scanf("%d", &n);
printf("Table of %d ", n);
for (i=1; i<=12; ++i)
{
p = i* n;
printf("%d * %4 = %d " n, i, p ); .
}
getch();
}
Output
Enter a number whose table is to print 6
6 * 1 = 6
6 * 2 = 12
6 * 3 =18
6 * 4 = 24
6 * 5 = 30
6 * 6 = 36
6 * 7 = 42
6 * 8 = 48
6 * 9 = 54
6 * 10 = 60
6 * 11 = 66
6 * 12 = 72

Example 8.3
Write down a program to generate the following output
Ch – 8 For Loop By Abdul Ghaffar Khan C8 lower left corner BC lower right corner

Example 8.3
void main(void) {
int x, y;
clrscr(); .
printf ("xc9");
for (x=1; x<72 ; ++x)
{
printf("xcd") ;
}
printf("xBB ");
// drawing vertical lines
for (x=1;x<10;++x)
{
if (x==5)
printf("xBA Welcome To Learning C xBA ");
printf("xBA xBA ");
}
Ch – 8 For Loop By Abdul Ghaffar Khan printf("xC8"); // drawing bottom line for (x=1;x<72;++x) { printf("xcd"); } printf("xBC ") ; getch(); }

Multiple assignments in the for loop
We can use more than one initialization statement and more than one Increment decrement statements however only one condition is allowed within a for loop. When used multiple assignments or increment commas separate each statement.
for( assignment I, asslgnment2; Condition; Increment1, intement2) .
{
body of loop
}

Example 8.3
#include<stdio.h>
#include<conio.h>
void main(void)
{
int x, y;
clrscr();
for(x = 1, y= 10; x<= 10; ++x, --y)
printf("x = %d Y = %d ",x,y);
getch(); ;
}
Output:
X= 1 Y = 10
X= 2 Y = 9
X= 3 Y = 8
X= 4 Y = 7
X=5 Y = 6
X=6 Y = 5
X=7 Y = 4
X=8 Y =3
X=9 Y =2
X=10 Y =1

The break statement
break statement is used to take immediate exit from the for loop. When break statement is executed the control immediately be transferred to the first statement following the for loop.
main()
{
for( exp_l ; exp_2; exp_3)
{
statement1;
statement2;
if( condition)
beak;
statement3;
statement4;
}
statement5;
statement6;
}

The continue statement
Continue statement is used to skip the remaining statement in a loop this statement immediately transfer the control to the increment or decrement expression in the loop
Ch – 8 For Loop By Abdul Ghaffar Khan main() { for( exp_l ; exp_2;exp_3) { statement 1; statement 2.; if( condition) continue; statement3; statement4; } statement5;. statement6; }

Nested for loop:
When a for loop is completely embedded ( enclosed) within another for loop, the structure is called nested for loop,
Ch – 8 For Loop By Abdul Ghaffar Khan for ( exp1 ; condition;exp2) { body-of-loop 1 for( exp3; condition2;exp4) { body-of-loop2 } }

Example 8.4 ( Factorials)
void main(void)
{
int i,j; long fact; .
clrscr();
for (i =1;i<=7;++i)
{
fact=l.
for (j=i; j> I; --j)
{
fact *= j;
}
printf(" %d! = %d ",i,fact);
}
getch();
}
Output:
1! = I
2! =2
3! =6
4! =24
5! = 120
6! = 720
7! = 5040

Example 8.5 ( Stars)
void main(void)
{
int I,j;
clrscr();
for (i =1;i<=10;++i)
{
for 0= 1; j<=i ; ++j)
{
printf('*'); ,
}
printf(" ");
}
getch();
}
Output:
*
**
***
****
*****
******
*******
********
*********
**********

http://www.ustudy.in	35
http://ghaffarkh.blogspot.com	28
http://ghaffarkh.blogspot.in	9
http://localhost	1
http://ghaffarkh.blogspot.ro	1
http://ghaffarkh.blogspot.pt	1
http://ghaffarkh.blogspot.be	1
http://ghaffarkh.blogspot.com.es	1
http://ghaffarkh.blogspot.co.nz	1
http://www.slideshare.net	1
http://ghaffar-khan.blogspot.com	1
http://ghaffarkh.blogspot.ru	1

For Loop

by Ghaffar Khan on Nov 26, 2008

Accessibility

Categories

Upload Details

Usage Rights

12 Embeds 81

Statistics

For Loop Presentation Transcript