using System;

public class Overflow
{
    private const int N = 80000000;

    [Benchmark]
    public static int NoCheck()
    {
        int sum = 0;
        for(int i=0; i<N; i++) {
          sum += 1;
        }
        return sum;
    }

    [Benchmark]
    public static int ImplicitCheck()
    {
        int sum = 0;
        bool flag = false;
        for(int i=0; i<N; i++) {
          try {
            flag = false;
            checked {
              sum += 1;
            }
          }
          catch(OverflowException) {
            flag = true;
          }
          if (flag)
            return -1;
        }
        return sum;
    }


    [Benchmark]
    public static int ImplicitCheckNoFlag()
    {
        int sum = 0;
        for(int i=0; i<N; i++) {
          try {
            checked {
              sum += 1;
            }
          }
          catch(OverflowException) {
            return -1;
          }
        }
        return sum;
    }


    [Benchmark]
    public static int ExplicitCheck()
    {
        int sum = 0;
        bool flag = false;
        for(int i=0; i<N; i++) {
          int r = sum+1;
          flag = !((r^(sum)) >= 0 || (r^(1)) >= 0);
          sum = r;
          if (flag)
            return -1;
        }
        return sum;
    }
}