Question

Develop an algorithm and a program in C that asks the user to enter a positive integer between 2 and 100,000. The program will then print to the screen the 10 prime numbers that are greater than or equal to the user's input.

Answer 1

Please find the required C script as the following:

//=================================================================

#include <stdio.h>

int ifprime(int num) // Function to check a prime number

{

int i,check=1;

for(i=2;i<=num/2;i++)

{

if(num%i==0)

{

check = 0;

}

}

return check;

}

int main(void) {

int input,print_count=0;

printf("Enter a positive number between 2 and 100000: ");

scanf("%d",&input);

while(input<2 || input>100000) // check the validity of an input

{

printf("Incorrect input!\nEnter a positive number between 2 and 100000: ");

scanf("%d",&input);

}

printf("The required 10 prime numbers are: ");

while(print_count<10) // Condition to print only 10 prime numbers

{

if(ifprime(input))

{

printf("%d ",input);

print_count++;

}

input++;

}

return 0;

}

//=================================================================

sample output:

Enter a positive number between 2 and 100000: -1
Incorrect input!
Enter a positive number between 2 and 100000: 4
The required 10 prime numbers are: 5 7 11 13 17 19 23 29 31 37