我正在尝试使用运算符重载来定义我的多项式类的基本操作(, – ,*,/)但是当我运行程序时它会崩溃并且我的计算机冻结.
UPDATE4
好.我成功完成了三次操作,剩下的唯一一次是划分.
这是我得到的:
polinom operator*(const polinom& P) const
{
polinom Result;
constIter i, j, lastItem = Result.poly.end();
Iter it1, it2, first, last;
int nr_matches;
for (i = poly.begin() ; i != poly.end(); i++) {
for (j = P.poly.begin(); j != P.poly.end(); j++)
Result.insert(i->coef * j->coef, i->pow + j->pow);
}
Result.poly.sort(SortDescending());
lastItem--;
while (true) {
nr_matches = 0;
for (it1 = Result.poly.begin(); it1 != lastItem; it1++) {
first = it1;
last = it1;
first++;
for (it2 = first; it2 != Result.poly.end(); it2++) {
if (it2->pow == it1->pow) {
it1->coef += it2->coef;
nr_matches++;
}
}
nr_matches++;
do {
last++;
nr_matches--;
} while (nr_matches != 0);
Result.poly.erase(first, last);
}
if (nr_matches == 0)
break;
}
return Result;
}
解决方法:
至于正确添加多项式函数,我推荐这个简单的逻辑:
polinom operator+(const polinom& P) const //fixed prototype re. const-correctness
{
polinom Result;
std::list<term>::const_iterator //fixed iterator type
i = poly.begin(), j = P.poly.begin();
while (i != poly.end() && j != P.poly.end()) {
//logic while both iterators are valid
}
//handle the remaining items in each list
//note: at least one will be equal to end(), but that loop will simply be skipped
while (i != poly.end()) {
Result.insert(i->coef, i->pow);
++i;
}
while (j != P.poly.end()) {
Result.insert(j->coef, j->pow);
++j;
}
return Result;
}
最后一部分也可能留给标准库函数
#include <iterator>
#include <algorithm>
//...
//handle remaining items in either list (if any)
std::copy(i, poly.end(), std::back_inserter(Result.poly));
std::copy(j, P.poly.end(), std::back_inserter(Result.poly));
…但使用list.insert可能会更简单:
Result.poly.insert(Result.poly.end(), i, poly.end());
Result.poly.insert(Result.poly.end(), j, P.poly.end());