Program to calculate length of string

#include<stdio.h>
#include<iostream.h>
#include<conio.h>
void count(char a[]);
void main()
{
clrscr();
char a[10],i;
cout<<"\n";
cout<<"enter a string";
cout<<"\n";
gets(a);
count(a);
getch();
}
void count(char a[])
 {
  int countt=0,i;
  for(i=0;a[i]!='\0';i++)
     {
      countt++;
     }
   cout<<"\n";
   cout<<"the length of string is"<<"\t"<<countt;
 }