Pensar en C++ (Volumen 1) - Grupo ARCO

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“Volumen1” — 2012/1/12 — 13:52 — page 503 — #541
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16.7. Introducción a los iteradores
}
int pop() {
require(top > 0, "Too many pop()s");
return stack[--top];
}
class iterator;
friend class iterator;
class iterator {
IntStack& s;
int index;
public:
iterator(IntStack& is) : s(is), index(0) {}
// To create the "end sentinel" iterator:
iterator(IntStack& is, bool)
: s(is), index(s.top) {}
int current() const { return s.stack[index]; }
int operator++() { // Prefix
require(index < s.top,
"iterator moved out of range");
return s.stack[++index];
}
int operator++(int) { // Postfix
require(index < s.top,
"iterator moved out of range");
return s.stack[index++];
}
// Jump an iterator forward
iterator& operator+=(int amount) {
require(index + amount < s.top,
"IntStack::iterator::operator+=() "
"tried to move out of bounds");
index += amount;
return *this;
}
// To see if you’re at the end:
bool operator==(const iterator& rv) const {
return index == rv.index;
}
bool operator!=(const iterator& rv) const {
return index != rv.index;
}
friend ostream&
operator