Is this code right for palindrome in string

Question

#include <iostream>
#include<string.h>

using namespace std;

int main ()

{

char str[50], flag;

int i, j;

cout << "Enter a string : ";
cin>>str;
cout<<str<<endl;

j = strlen(str)- 1;

for (i = 0; i < j; i++,j--)

{

if(str[i++]==str[i--])
flag=1;
}
if(flag)
cout<<"palindrome";
else
cout<<"not palindrome";

return 0;
}