how to create an array without specifying size in c++ code example

Example 1: 1d fixed length arrays c++

void initarr(int arrgender[TOT_MALE][TOT_FEMALE])
  {
      for(int a =0; a < TOT_MALE;a++)
      {
          for(int b = 0; b < TOT_FEMALE;b++)
          {
              arrgender[a][b] = 0;
          }
      }

Example 2: why cin take more characters then the size of array in C++

why cin take more characters then the size of array in C++