The c++ output is unbelievable

#include <iostream>#include <cstdio>using namespace std;int main(){    int t=1;    printf("%d %d %d %d %d\n",++t,t++,++t,t++,++t);    int x=1;    cout<<++x<<" "<<x++<<" "<<++x<<" "<<x++<<" "<<++x<<endl;    return 0;}// output:6 4 6 2 66 4 6 2 6