LOOP Complete Topic

Q: what is loop? Ans: A statement or set of statements that is executed repeatedly is known as loop, or iteration. There are three types of loops available in C language.

1.       For Loop

i)        Counter loop

2.       Conditional Loop

ii)       While loop

iii)     do-while loop

Q: What is “while” loop? Ans: while loop is the simplest loop of C language. This loop executes one or more statements while the given condition remains true. Syntax:  While(condition)              statement;

The syntax of compound statement as :

While (condition)

{

Statement 1;

Statement 2;

:

Statement N;                                                      

}

ü  write a program that displays “Pakistan” for five times using while loop.(int n; n=1; while(n<=5); n++; and \n).

ü  write a program that displays counting from 1 to 10. (int n; while(condition) n++

ü  write a program that displays first five numbers and their sum using while loop.(int c,sum; sum=0 while(condition) sum=sum+c;)

ü  write a program that displays first 5 numbers with their squares using while loop.(n=1;, while(n<=5), printf(“%d %d\n”,n,n*n);, n++

ü  write a program that inputs a number from the user and displays the factorial of that number using while loop.

ü  What is do-while loop? The do-while is an iterative control in  c language. This loop execute one or more statements while the given condition is true. In this loop, the condition comes after the body of loop. The loop is important in a situation where a statement must be executed at least once.

Syntax:  do

                {

                                Statement 1;

                                Statement 2;

                                :

                                :

                                Statement N;

                }

                While (condition);

While loop:Y in while loop, conditions comes before the body of the loop. Y if condition is false in the beginning, while loop is never executed. Y the semicolon is not used after the condition.

do-while loop: Y in do-while loop, condition comes after the body of the loop. Y do-while is executed at least once even if conditions is false in the beginning. Y semicolon is used after the condition.

Program: write a program that displays first ten odd numbers using do-while loop.