c语言点分十进制IP转整型

#include <iostream>
using namespace std;
char* intToBin(int a)
{
  char *str = (char *)malloc(8);
  memset(str, '0', 8);
  str[8] = '\0';
  //cout << strlen(str) << endl;
  int i = 7;
  while (a && i >= 0) {
    //cout << i << endl;
    //cout << a % 2;
    str[i--] = (a % 2 + '0');
    a /= 2;
  };
  return str;
}
int binToInt(const char *str)
{
  int ans = 0;
  for (int i = strlen(str) - 1; i >= 0; i--) {
    ans += (str[i] - '0') * (pow(2, strlen(str) - 1 - i));
  }
  return ans;
}
int arr[4] = { 0 };
int fun(const char *str) 
{
  int k = 3;
  for (int j = strlen(str) - 1, m = 1; j >= 0; j--) {
    if (str[j] == '.') {
      m = 1;
      k--;
      continue;   
    }
    arr[k] += m * (str[j] - '0');
    m = m * 10;
  }
  /*cout << arr[0] << endl;
  cout << arr[1] << endl;
  cout << arr[2] << endl;
  cout << arr[3] << endl;*/
  //cout << strlen(str) << endl;
  return 0;
}
int main()
{
  const char *s = "127.0.0.1";
  fun(s);
  char *str = (char *)malloc(33);
  memset(str, '\0', 33);
  for (int i = 0; i < 4; i++) {
    //cout << intToBin(arr[i]) << endl;
    memcpy(str + (i * 8), intToBin(arr[i]), 8);
  }
  cout << str << endl;
  cout << binToInt(str) << endl;
  //cout << fun(s) << endl;
  //cout << intToBin(127) << endl;
  return 0;
}