Question

Write a C program that …

• reads one unsigned long int value  N  from standard input
  • assume that the value of  N  that is entered by the user is greater than  1 
• prints (to standard output) …
  • the greatest prime number that divides of  N 

Answer 1

#include <stdio.h>

int main()
{
long int N,out,i,j,f;
scanf("%ld",&N);
for(i=1;i<=N;i++)
{
f=0;
for(j=1; j<=N; j++)
{
if(i%j==0)
f++;
}
if(f==2)
{
if(N%i==0)
out=i;
}
}
printf("%ld",out);

return 0;
}