factorial trailing c++

general
,
1

#include
using namespace std;
int fact(int );
int main()
{
int n,i,t,q;
cin>>n;
for(i=0;i<n;i++)
{
cin>>t;
int count =0;
q=fact(t);
while(q%10==0)
{
q=q/10;
count++;
}
cout<<count;
}
return 0;
}
int fact(int a)
{
int i=1,j;
for(j=1;j<=a;j++)
i=i*j;

return i;

}
2

can you be more specific what do you want to ask .

3

You are suffering from overflow because numbers after 20! cannot be stored in any data type in C++. You need to make some observations on the question, like when does a trailing 0 come in the factorial etc.

1 Like
4

There’s no need to find the factorials. Just count the number of 5’s in n!, that would be equal to the number of 0’s in n!.
(This is because each 2 & 5 pair form one 0, and number of 5’s is than that of 2’s.)