Metric System or Go Fuck Your Mother

#include <string>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

double smaller(double a, double b)
{
    if (a < b) return a;
    return b;
}

double larger(double a, double b)
{
    if (a > b) return a;
    return b;
}

double to_meters(double v, string unit)
{
    double sum = 0;
    if (unit == "m") {
        sum += v;
    } else if (unit == "cm") {
        sum = sum + (v/100);
    } else if (unit == "in") {
        sum = sum + ((v * 2.54)/100);
    } else if (unit == "ft") {
        sum = sum + ((v * 12 * 2.54)/100);
    }
    return sum;
}

int main()
{
    double last_smallest = -1, last_largest = -1;
    double amount = 0, cm, in, ft, m, total = 0;//, y;
    vector<string> smallest;
    vector<string> largest;
    vector<string> all;
    vector<double> all_in_meters;
    string unit, smallest_s, largest_s;
    cout << "Enter a scale amount and the scales respective unit: " << "\n";

    while (cin >> amount >> unit) {
        amount = amount;
        unit = unit;

        if (last_smallest == -1 and last_largest == -1) {
            last_smallest, last_largest = amount;
            smallest.push_back( to_string(amount) + unit );
            largest.push_back( to_string(amount) + unit );
        } else {
            if (smaller(last_smallest, amount) < last_smallest) {
                last_smallest = amount;
                smallest_s = (to_string(amount) + unit);
                smallest.push_back( smallest_s );
            } else if (larger(last_largest, amount) > last_largest) {
                last_largest = amount;
                largest_s = (to_string(amount) + unit);
                largest.push_back( largest_s );
            }
        }

        if (unit == "cm") {
            cm = amount;
            total += to_meters(amount, unit);
            cout << "There are " << cm << "cm in " << amount << "cm\n";
        } else if (unit == "in") {
            in = amount * 2.54;
            total += to_meters(amount, unit);
            cout << "There are " << in << "cm in " << amount << "in\n";
        } else if (unit == "ft") {
            ft = amount * 12;
            total += to_meters(amount, unit);
            cout << "There are " << ft << "in in " << amount << "ft\n";
        } else if (unit == "m") {
            total += to_meters(amount, unit);
            cm = amount * 100;
            cout << "There are " << cm << "cm in " << amount << "m\n";
        } else {
            cout << "Did not recognize that unit, your request is rejected. Sorry bro...\n";
        }

        all.push_back( to_string(amount) + unit );
        all_in_meters.push_back( to_meters(amount, unit) );
    }
    cout << "Your total inputs turned out to be: " << total << " meters.\n";
    if (largest.size() > 0)
        cout << "The largest input value so far: " << largest[largest.size() - 1] << "\n";
    if (smallest.size() > 0)
        cout << "The smallest input value so far: " << smallest[smallest.size() - 1] << "\n";
    if (all.size() > 0)
        cout << "All inputs in original order: \n";
        for (int i=0; i < all.size(); ++i)
            cout << "Input " << i << "\t" << all[i] << "\n";
    if (all_in_meters.size() > 0)
        cout << "All inputs (converted to meters) in sorted order: \n";
        sort( all_in_meters.begin(), all_in_meters.end() );
        for (int i=0; i < all_in_meters.size(); ++i)
            cout << "Input " << i << "\t" << all_in_meters[i] << "\n";
    // while (cin >> x) {
    // }

    // cout << "Enter two integers in sequence: " << "\n";
    // while (cin >> x >> y) {
    //  // cout << "Integers: " << x << " " << y << "\n";
    //  if (x == y) {
    //      cout << "The two numbers entered are equal" << "\n";
    //  } else {
    //      if (larger(x,y) - smaller(x, y) <= 1.0/100) {
    //          cout << "The numbers entered are almost equal" << "\n";
    //      } else {
    //          cout << "The smaller value is: " << smaller(x,y) << "\n";
    //          cout << "The larger value is: " << larger(x,y) << "\n";
    //      }
    //  }
    // }
    // for (int a, b; cin>>a>>b;) {
    //  cout << a << " " << b << "\n";
    // }
    return 0;
}