reverse string efficient in cpp without using function

1#include <iostream>
2using namespace std;
3int main()
4{
5    char str[] = "Reverseme";
6    char reverse[50];
7    int i=-1;
8    int j=0;
9         /*Count the length, until it each at the end of string.*/ 
10          while(str[++i]!='\0');
11           while(i>=0)
12                    reverse[j++]=str[--i];
13            reverse[j]='\0';
14      cout<<"Reverse of  a string is"<< reverse;
15      return 0;
16}