Linear Equation Solver

solver.cpp

#include <iostream>
#include <regex>
#include <cstdlib>

using namespace std;

double* getInput();
bool undefined(double*);
double a(double*);
double c(double*, double);

int main(int argc, char const* argv[])
{
  double* input = getInput();

  if ( undefined(input) )
    cout << "Undefined\n";
  else
    cout << "Output:\n"
         << "(" << a(input) << ", " << c(input, a(input)) << ")\n";

  return 0;
}

double* getInput() {
  string rawInput;
  static double input[4];
  regex nums("(\\d|\\.)+");
  smatch result;

  cout << "Input:\n";
  cin >> rawInput;

  sregex_iterator matches(rawInput.begin(), rawInput.end(), nums);

  for ( int i = 0; i < 4; i++ ) {
    result = *matches;
    input[i] = atof( result.str().c_str() );
    matches++;
  }

  return input;
}

bool undefined(double* input) {
  bool ans;

  if ( input[0] == input[2] )
    ans = true;
  else
    ans = false;

  return ans;
}

double a(double* input) {
  return ( input[1] - input[3] ) / ( input[0] - input[2] );
}

double c(double* input, double slope) {
  return input[1] - slope * input[0];
}