Question

write an algorithm to check a number is prime number or not​

Answer 1

Answer:

Aim:

Write a C program to check whether the given number is prime or not.

Algorithm:

Step 1: Start

Step 2: Read number n

Step 3: Set f=0

Step 4: For i=2 to n-1

Step 5: If n mod 1=0 then

Step 6: Set f=1 and break

Step 7: Loop

Step 8: If f=0 then

print 'The given number is prime'

else

print 'The given number is not prime'

Step 9: Stop

Program code

#include<stdio.h>

#include<conio.h>

void main( )

{

clrscr();

int n,i,f=0;

printf("Enter the number: ");

scanf("%d",&n);

for(i=2;i<n;i++)

{

if(n%i==0)

{

f=1;

break;

}

}

if(f==0)

printf("The given number is prime");

else

printf("The given number is not prime");

getch();

}

Output

Enter the number : 5

The given number is prime

Explanation:

hope it helps you

Answer 2

An algorithm to check a number is a prime number or not​:

• Step 1: Start

• Step 2: Taking initialization of N, temp=1, i=2

• Step 3: Read N from the user

• Step 4: If num<=1            // Numbers which are less than 1 are not considered as the prime number.

           Display "N is not a prime number"

           Go to step 7

• Step 5: Repeat the steps until i<[(c/2)+1]

                    If the remainder of the number divided by j equals 0,

                   Set temp=0

                   Go to step 6

                            i=i+1

• Step 6: If temp==0,

           Display N+" is not a prime number"

       Else  

           Display N+" n is a prime number"

• Step 7: End