Nested for Loop

It is possible to nest one for loop inside another. To demonstrate this structure, we'll concoct a program that will print the multiplication table:


included files
void main()
{
 int cols,rows;
 for(row=1;rows<13;rows++)   /*outer loop*/
  {
   for(cols=1;cols<13;cols++) /*inner loop*/
   printf("%3d",cols*rows);
   printf("\n");
  }
 getch();
}


The output will be:
1   2   3   4   5    6   7    8   9    10   11    12
2   4   6   8.....................................24
.   .   .  .....................................  36
.   .   .  .....................................  48
.   .   .  .....................................  60
.   .   .  .......................................72
.   .   .  .......................................84
.   .   .  ........................................
12  24  36  48 60   72  84   96  108  120   132  144




If you have any question, you can ask me freely!

The for Loop

It is often the case in programming that you want to do something a fixed number of times. Perhaps you want to calculate the paychecks for 120 employees  or print out the squares of all the numbers from 1 to 50. The for loop is ideally suited for such cases.


Let's look at a simple example of a for loop which will print numbers from 0 to 9:


included files
void main()
{
 int count;
 clrscr();
 for(count=0;count<10;count++)
 printf("Count=%d\n",count);
 getch();
}


The output will be:
   Count=0
   Count=1
   Count=2
   Count=3
   Count=4
   Count=5
   Count=6
   Count=7
   Count=8
   Count=9


This program's role in life is to execute a printf() statement 10 times.


Structure of the for Loop:
The loop expression is divided by semicolons into three separate expressions: the "initialize expression", the "test expression", and the "increment expression".
==================================================
Expression                                    Name                                     Purpose
==================================================
count=0                          Initialize expression         Initializes loop variable
count<10                            Test expression              Tests loop variable
count++                          Icrement expression         Increments loop variable
---------------------------------------------------------------------------------------------


The Body of the Loop:
Following the keywords for and the loop expression is the body of the loop: that is, the statement (or statements) that will executed each time round the loop. In our above example, there is only one statement:


printf("Count=%d\n",count);


Note that this statement is terminated with a semicolon, wheras the for with the loop expression is not.




If you have any questions, you can ask me freely!