CHECKING FOR PRIME NUMBER --- unix lab

CHECKING FOR PRIME NUMBER

AIM:

            To write a Shell Program to check if the Number is a Prime Number or a Composite Number.

ALGORITHM:

Step 1: Start

Step 2: Read the Number as ‘n’

Step 3: Initialize the value of ‘t’ to 0 and solve the expression i=n-1

Step 4: While ‘i’ is greater than or equal to 2, perform the following steps.

Step 5: Solve p=n%i

Step 6: Check the condition (p=0) and then solve t=t+1

Step 7: End the If Condition

Step 8: Solve the expression i=i-1

Step 9: If ‘t’ is greater than 0, print “The Number is not a Prime Number”

Step 10: If the condition is not satisfied, print “The Number is a Prime Number”

SHELL PROGRAM:

echo "Enter a Number"

read n

i=`expr $n - 1`

t=0

while [ $i -ge 2 ]

do

p=`expr $n % $i`

if [ $p -eq 0 ]

then

t=`expr $t + 1`

fi

i=`expr $i - 1`

done

if [ $t -gt 0 ]

then

echo "The Number $n is not a Prime Number"

else

echo "The Number $n is a Prime Number"

fi

SAMPLE OUTPUT:

[Cseb19@sathish-desktop]# sh prime.sh

Enter a Number

2

The Number 2 is a Prime Number

[Cseb19@sathish-desktop]# sh prime.sh

Enter a Number

4

The Number 4 is not a Prime Number

RESULT:

            Thus the Shell Program to check if the given number is prime or not, was executed and the output was verified.