#include <stdio.h>
int main()
{
int a,b,c,d,e;
while (scanf("%d %d %d %d",&a,&b,&c,&d))
{
if ((b-a)==(c-b)) {
e=d+(b-a);
}
else
{
e=d*(d/c);
}
printf("%d %d %d %d %d",a,b,c,d,e);
}
}

while (scanf("%d %d %d %d",&a,&b,&c,&d) == 4)

或是

while (scanf("%d %d %d %d",&a,&b,&c,&d) != EOF)