Question

design c program using functions. (a).generate prime numbers of given range. (b).prime number or not.

Answer 1

#include <stdio.h>
void fun(int , int);
int main(int argc, char *argv[])
{ int i , n1 , n2 , res;
if(argc != 3)
{printf("please pass atleast two arguments");
    return 0;
}
     n1 = atoi(argv[1]);
     n1 = n1+1;
     n2 = atoi(argv[2]);
     fun(n1 , n2);
    return 0;
}
void fun(int n1, int n2)
{int i , j, count;
        for(i=n1;i<n2;i++)
        {
            count = 0;
            for(j=2;j<n1/2;j++)
            {if(i%j == 0)
                {count ++;}
            }
        if(count == 0)
        {printf("%d\t",i);}
        }    
}

Answer 2

find is a number is prime or not-----------------------

#include <stdio.h>
int fun(int);
int main(int argc, char *argv[])
{ int i , n1 , res;
if(argc != 2)
{printf("please pass atleast one argument");
    return 0;
}
     n1 = atoi(argv[1]);
     res = fun(n1);
     if(res == 0)
     printf("%d is a prime number",n1);
     else
     printf("%d is not a prime number",n1);
    return 0;
}

int fun(int n1)
{int j, count, res=0;
        for(j=2;j<n1;j++)
            {if(n1%j == 0)
                {   return 1;}
            }
        return 0;
        }

Answer 3

#include <stdio.h>
void isPrime(int);
void isPrimeOrNot(int);
int main()
{
    int n,p;
    printf("Prime number upto number");
    scanf("%d",&n);
    isPrime(n);
    printf("\nenter a number");
    scanf("%d",&p);
    isPrimeOrNot(p);
    return 0;
}
void isPrime(int n)
{
    int i,fact,j;
    printf("Prime Numbers are: \n");
    for(i=1; i<=n; i++)
    {
        fact=0;
        for(j=1; j<=n; j++)
        {
            if(i%j==0)
                fact++;
        }
        if(fact==2)
            printf("%d " ,i);
    }
  }
void isPrimeOrNot(int y)
{
    int i,flag=0;
    for(i=2;i<=y/2;i++)
    {
        if(y%2==0)
        {
            flag=1;
            break;
        }
    }
    if(flag==1)
    printf("number is not prime");
    else
    printf("number is prime %d",y);
}