Exercise 4-5

 

#include <stdio.h>

 

int main() {

    int i,num;

    i=0;

    printf("enter a number: ");

    scanf("%d",&num);

    for (i;i<=num;i=i+1)

        printf("*");

   

    return 0;

}

Exercise 4-11

 

#include <stdio.h>

 

int main() {

    int i,j,num,prime;

    i=2;

    j=2;

    prime=1;

    printf("enter a number: ");

    scanf("%d",&num);

    for (i;i<=num;i++){

        for (j;j<i;j++){

            if (i%j==0){

                prime=0;

                j=i+1;

            }

        }

        if (prime==1)

           printf("%d ",i);

 

        j=2;

        prime=1;

    }

 

    return 0;

}

Exercise 4-10

 

int main() {

    int i,num,prime;

    i=2;

    prime=1;

    printf("enter a number: ");

    scanf("%d",&num);

    for (i;i<num;i++){

        if (num%i==0){

            prime=0;

            i=num+1;

        }

    }

    if (prime==1)

        printf("your number is a prime number.");

    else

        printf("your number is not a prime number.");

 

    return 0;

}