Answer:
#include <stdio.h>
int main(void) {
unsigned long n = 1;
for(unsigned long i=10; i<=30; i+=2) {
n *= i;
}
printf("%lu",n);
return 0;
}
Explanation:
The output is: 111588212736000
The answer will take 47 bits, so you have to use 64-bit longs. An int is 32 bit thus will give the wrong answer due to a numeric overflow.