please convert this C++ code to C

#include<bits/std++.h>
#define ll long long int
#define ld long double
#define ite iterator
#define mp make_pair
#define ff first
#define ss second
#define pb push_back
#define ioS ios::sync_with_stdio(false);
#define fr(i,x,n) for(int i=x;i<n;i++)>
#define re0 return 0 ;
#define mod 1000000007
using namespace std ;

ll  n,i,j,md,hi,lo ,mx,h,k,flag,sum,x,t,y,w,ans,q,hsh  ;
int main()
{
    cin >> t ;
    while(t--){
    string s;
    flag= 0 ;
    cin >> s;
     mx = 0;
   string::iterator itr1,itr2;

    for(itr1 = s.begin(); itr1 != s.end(); ++itr1)
        for( itr2 = itr1 + 1; itr2 != s.end(); ++itr2)
            mx = max(mx,(ll)(mismatch(itr1, itr1 + (s.end() - itr2), itr2).ff - itr1));
    if(flag==0)cout << mx << endl ;
    else cout << "0\n" ;
}
}