From 95ffb98a8d08ef20672d6ef91ea8fb4320c5ea85 Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@iut-bm.univ-fcomte.fr>
Date: Mon, 14 Feb 2011 11:00:58 +0100
Subject: [PATCH] Use std::vector and stl algorithms for cost_func.
---
cost_func.cpp | 58 ++++++++++++++++++++++-----------------------------
cost_func.h | 6 +++---
2 files changed, 28 insertions(+), 36 deletions(-)
diff --git a/cost_func.cpp b/cost_func.cpp
index 7311199..12c20f6 100644
--- a/cost_func.cpp
+++ b/cost_func.cpp
@@ -1,58 +1,50 @@
#include <algorithm>
-#include <cstdlib>
-#include <cstring>
+#include <tr1/functional>
+#include <numeric>
#include <iterator>
#include <sstream>
+#include <stdexcept>
#include "cost_func.h"
cost_func::cost_func(const char* param)
{
- int len = strlen(param);
- char tmpbuf[len + 1];
- char* tmp = tmpbuf;
- memcpy(tmp, param, len + 1);
- degree = std::count(tmp, tmp + len, ',');
- factor = new double[degree + 1];
- for (int i = degree ; i > 0 ; i--) {
- char* next = strchr(tmp, ',');
- *next++ = '\0';
- std::istringstream(tmp) >> factor[i];
- tmp = next;
+ std::istringstream paramstream(param);
+ std::string token;
+ while (std::getline(paramstream, token, ',')) {
+ std::istringstream str(token);
+ double f;
+ if ((str >> f) && str.eof())
+ factors.push_back(f);
+ else
+ throw std::invalid_argument("cost_func(): "
+ "cannot parse \"" + token + "\"");
}
- std::istringstream(tmp) >> factor[0];
+ if (factors.empty())
+ throw std::invalid_argument("cost_func(): no factor");
}
cost_func::~cost_func()
{
- delete[] factor;
-}
-
-cost_func& cost_func::operator=(const cost_func& ref)
-{
- if (&ref != this) {
- degree = ref.degree;
- delete[] factor;
- factor = new double[degree + 1];
- memcpy(factor, ref.factor, (degree + 1) * sizeof *factor);
- }
- return *this;
}
double cost_func::operator()(double amount) const
{
- double result = factor[degree];
- for (int i = degree - 1; i >= 0 ; i--)
- result = amount * result + factor[i];
- return result;
+ using std::tr1::bind;
+ using std::tr1::placeholders::_1;
+ using std::tr1::placeholders::_2;
+ return std::accumulate(++factors.begin(), factors.end(), factors.front(),
+ bind(std::plus<double>(),
+ bind(std::multiplies<double>(), amount, _1),
+ _2));
}
std::string cost_func::to_string()
{
std::ostringstream oss;
- std::reverse_copy(factor + 1, factor + degree + 1,
- std::ostream_iterator<double>(oss, ", "));
- oss << factor[0];
+ std::copy(factors.begin(), --factors.end(),
+ std::ostream_iterator<double>(oss, ", "));
+ oss << factors.back();
return oss.str();
}
diff --git a/cost_func.h b/cost_func.h
index d7310d2..c6984d2 100644
--- a/cost_func.h
+++ b/cost_func.h
@@ -3,6 +3,7 @@
#include <iostream>
#include <string>
+#include <vector>
// Define a polynomial function
// The factors are given at construction time, in a C-style string,
@@ -11,13 +12,12 @@ class cost_func {
public:
cost_func(const char* param);
~cost_func();
- cost_func& operator=(const cost_func& ref);
double operator()(double amount) const;
std::string to_string();
+
private:
- int degree;
- double* factor;
+ std::vector<double> factors;
};
#endif // !COST_FUNC_H
--
2.39.5