Not able to pass all testcase

#1

please provide the correction in my code to pass all testcase.
Problem:-Tavas and Saddas
code:-

#include
using namespace std;
#include <math.h>

int numberofdigit(int n)
{
int k=0;
while(n>0)
{
n=n/10;
k++;
}
return k;
}
int main()
{
int n;
cin>>n;
int k=numberofdigit(n);

int x=0;

 x+=k*(k-1); 

for(int i=0;i<k;i++)
{
	int rem=n%10;
	if(rem==7)
	 x+=pow(2,i);
	n=n/10;
}
x++;
cout<<x;

return 0;

}

#3

this statement is incorrectly written
it has to be x = ( 1 << k )

#4

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