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// Example program
#include <iostream>
#include <sstream>
#include <string>
#include <array>
#include <algorithm>
struct Term {
Term() : coefficient(0), variable(0), subscript(0) {}
Term(int coefficient, char variable, int subscript)
: coefficient(coefficient), variable(variable), subscript(subscript) {}
int coefficient;
char variable;
int subscript;
struct Comparer
{
inline bool operator() (const Term& t1, const Term& t2)
{
return (t1.subscript < t2.subscript);
}
};
};
std::ostream& print_term(std::ostream& os, const Term& term, bool first)
{
if (term.coefficient != 0)
{
if (!first && term.coefficient > 0)
os << "+";
os << term.coefficient << term.variable << term.subscript;
}
return os;
}
constexpr int Num_Terms = 3;
std::ostream& operator<<(std::ostream& os, const std::array<Term, Num_Terms>& terms)
{
if (Num_Terms == 0) return os;
print_term(os, terms[0], true);
for (int i = 1; i < Num_Terms; i++)
{
print_term(os, terms[i], false);
}
return os;
}
int main()
{
std::string input = "3x2+2x1+4x3=16";
// process input LHS
std::istringstream ss(input);
std::array<Term, Num_Terms> terms;
for (int i = 0; i < Num_Terms; i++)
{
ss >> terms[i].coefficient;
ss.get(terms[i].variable);
ss >> terms[i].subscript;
}
// process input RHS
std::string rhs;
getline(ss, rhs);
std::sort(terms.begin(), terms.end(), Term::Comparer());
// 2x1+3x2+4x3=16
std::cout << terms << rhs << std::endl;
}
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