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    <p>Okay, now that Vlad has decided how he's <em>going</em> to do it, here's how I'd do it:</p> <pre><code>#ifndef _polinom_h #define _polinom_h #include &lt;iostream&gt; #include &lt;list&gt; #include &lt;cstdlib&gt; #include &lt;cmath&gt; #include "infix_iterator.h" using namespace std; char var; class polinom { class term { double coef; int power; ostream &amp;write(ostream &amp;os) const { // At least to me, the logic is easier to follow if we // handle one piece at a time. // It may be longer, but I think it's easier to understand. // First, if the coefficient is negative, subtract the term instead of adding it. if (coef &lt; 0) // backspace over the "+ " and print '- ' in its place. os &lt;&lt; "\b\b- "; // Then print the absolute value of the coefficient (if needed). if (fabs(coef) != 1) os &lt;&lt; fabs(coef); // Then print the var (if needed) if (power != 0) os &lt;&lt; var; // then print the power (if needed) if (abs(power) &gt; 1) os &lt;&lt; "^" &lt;&lt; power; // And we're done. return os; } // support inserting a term into a stream. friend std::ostream &amp;operator&lt;&lt;(std::ostream &amp;os, term const &amp;t) { return t.write(os); } public: term(double c=0.0, int p=0) : coef(c), power(p) {} bool read(std::ostream &amp;os, std::istream &amp;is, int num) { // This is only slightly modified from the originally posted question os &lt;&lt; "\nTerm " &lt;&lt; num &lt;&lt; ": coef = "; is &gt;&gt; coef; if (coef == 0.0) return false; if (coef != 0.0) { os &lt;&lt; " grade = "; is &gt;&gt; power; } return true; } bool operator&lt;(term const &amp;other) const { // order by descending powers. return other.power &lt; power; } }; list&lt;term&gt; poly; public: void read(int id) { term t; int nr_term = 1; std::cout &lt;&lt; "P: " &lt;&lt; id; // Read and save individual terms: while (t.read(std::cout, std::cin, nr_term++)) poly.push_back(t); } void write(char var) { // sort the polynomial so the highest powers come first. poly.sort(); // save the variable name for later use. ::var = var; // Print out all the terms: std::copy(poly.begin(), poly.end(), infix_ostream_iterator&lt;term&gt;(std::cout, " + ")); } }; #endif </code></pre> <p>Using this is pretty trivial:</p> <pre><code>#include "polynom.h" int main() { polinom p; p.read(1); p.write('x'); return 0; } </code></pre>
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    1. POBasic polynomial reading using linked lists
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    1. USJerry Coffin
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    1. COmaybe it works, but what is inside infix_iterator.h?
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    2. CO@Vlad: Oops. Sorry 'bout that. See: http://groups.google.com/group/comp.lang.c++/msg/a746a588cedfa44b. It's basically like an ostream_iterator except that it only prints delimiters between items instead of after every one.
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