Page 189 - Computer science 868 Class 12
P. 189
b. Print whether the number n is a prime number or not.
int c=0;
for(int i=1; i<=n; i=i+1)
{
if(n%i==0)
{
c++;
}
}
if(c==2)
System.out.println(n+ " is a prime number");
else
System.out.println(n+ " is not a prime number");
The above example finds the number of factors of the number n and checks if the number of factors is 2 (which is
the condition of the prime number).
7.3.2 while Loop
Java ‘while’ loop executes a set of statements repeatedly for a certain number of time depending on the given condition.
As soon as the control statement does not match the condition, the loop terminates. It is known as an entry-controlled
loop as the condition is checked before the loop starts executing.
Syntax:
initialisation;
while(condition for testing)
{
// job performed by the body of the loop;
increment or decrement;
}
For example:
a. int i=5;
while(i<=20)
{
System.out.println(i);
i=i+5;
}
The above example prints all the multiples of 5 up to 20.
b. Print whether the number (n) is a prime number or not.
int c=0, i=1;
while(i<=n)
{
if(n%i==0)
{
c++;
}
i=i+1;
}
if(c==2)
System.out.println(n+ " is a prime number");
else
System.out.println(n+ " is not a prime number");
187
Statements and Scope 187

