Why bad_alloc error?

Question

C++ / C#

A simple "a+b from a file on one line" task. On startup, bad_alloc occurs. Tell me, what's wrong?

error text

terminate called after throwing an instance of 'std::bad_alloc'
what(): std::
bad_alloc
Please contact the application's support team for more information.

the code

#include <fstream>
#include <vector>

void do_sum(std::vector<int>& v_max, std::vector<int>& v_min) //сложение
{
  int i_max=v_max.size(), i_min=v_min.size();
  int temp=0;
  do{
      i_min--; i_max--;
      temp=v_max[i_max]+v_min[i_min];
      v_max[i_max]=temp%10;
      i_max!=0?(v_max[i_max-1]+=temp/10):v_max[i_max]=temp;
    }while(i_min>0);
}

void do_read(std::vector<int>& v1,std::vector<int>& v2, std::string filename) // считывание
{
  std::ifstream input_file(filename);
  char c='0';
  bool flag=true;
  while(flag){
      input_file>>c;
      if (c!=' ') v1.push_back(static_cast<int>(c-'0')); else flag=false;
    }

  while(input_file.get(c))
    {
      v2.push_back(static_cast<int>(c-'0'));
    }
  input_file.close();
}

void do_write(std::vector<int>& v, std::string filename)  // запись
{
  int size=v.size();
  std::ofstream output_file(filename);
  for(int i=0; i<size; i++)
    output_file<<v[i];
  output_file.close();
}

int main()
{
  std::string filenameIn="INPUT.txt", filenameOut="OUTPUT.txt";
  std::vector<int> v1,v2;
  do_read(v1,v2,filenameIn);
  if (v1.size()>=v2.size())
    {
      do_sum(v1,v2);
      do_write(v1,filenameOut);
    }
  else
    {
      do_sum(v2,v1);
      do_write(v2,filenameOut);
    };
  return 0;
}

Answer 1

You read the file incorrectly and push_back never stops and the entire memory is consumed.