nbrito_chall.c

#include <stdio.h>
#include <arpa/inet.h>

// 192.168.0.133    --      25 bits

int main(){
  unsigned int var1, var2, var3;
  unsigned int address = 0xc0a80085;
  var1 = ~(0xffffffff >> 25);
  // var1_>> = 0x7f
  // var1_final = 0xffffff80
  // address -- 0xc0a80085
  var2 = (ntohl(address) & var1) + 1;
  // var2_prim = ntohl(address) = 0x8500a8c0
  // var2_sec = (ntohl(address) & var1) = 0x8500a880
  // var2_final = (ntohl(address) & var1) + 1 = 0x8500a881
  var3 = (1 << (32 - 25));
  // var3 = (32 - 25) = 7
  // var3 = (1 << 7) = 0x80
  printf("%x", var3);
}

// var3 = (1 << (32 - bits)) - 2;