Function without arguments and with a return value

Input:

#include <stdio.h>

int getInteger();

int main()

{

int n, i, flag = 0;

n = getInteger(); // no argument is passed   

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

{

if(n%i==0)

{

flag = 1;

break;

}

}

if (flag == 1)

printf("%d is not a prime number.", n);

else

printf("%d is a prime number.", n);

return 0;

}

int getInteger() // returns integer entered by the user

       

{

int n;

printf("Enter a positive integer: ");

scanf("%d",&n);

return n;

}

Output:

Enter a positive integer: 4

4 is not a prime number

-----------------------------------------------------------------------------------

Enter a positive integer: 5

5 is a prime number

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The empty parentheses in the n = getInteger(); statement indicates that no argument is passed to the function. And, the value returned from the function is assigned to n.

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