C++ Institute CPP 問題集

質問 1：
Which are NOT valid instantiations of priority_queue object:
# include <iostream>
# include <deque>
# include <list>
# include <queue>
# include <vector>
using namespace std;
int main()
{
deque<int> mydeck;list<int> mylist; vector<int> myvector;
priority_queue<int> first;//line I
priority_queue<int, deque<int> > second;//line II
priority_queue<int> third(first);//line III
priority_queue<int, list<int> > fourth(third);//line IV
priority_queue<int, vector<int> > fifth(myvector.begin(), myvector.end());//line V return 0;
}
A. line V
B. line III
C. line IV
D. line I
E. line II
正解：C

質問 2：
What will happen when you attempt to compile and run the following code?
# include <iostream>
# include <map>
# include <vector>
# include <sstream>
# include <string>
using namespace std;
int main() {
int t[] = { 3, 4, 2, 1, 0, 3, 4, 1, 2, 0 };
vector<int> v(t, t + 10);
multimap<int, string> m;
for (vector<int>::iterator i = v.begin(); i != v.end(); i++) {
stringstream s;s << *i << *i;
m.insert(pair<int, string>(*i, s.str()));
}
pair<multimap<int, string>::iterator, multimap<int, string>::iterator> range; range = m.equal_range(2);
for (multimap<int, string>::iterator i = range.first; i != range.second; i++) { cout << i?>first << " ";
}
return 0;
}
The output will be:
A. 2
B. 1 3
C. 0 2
D. 2 2
E. 1 2
正解：D

質問 3：
What happens when you attempt to compile and run the following code?
# include <deque>
# include <list>
# include <iostream>
using namespace std;
int main ()
{
list<int>l1;
deque<int>d1;
for(int i=0; i<5; i++)
{
l1.push_back(i);l1.push_front(i);
d1.push_back(i);d1.push_front(i);
}
for(int i=0; i<d1.size(); i++)
{
cout<<d1[i]<<" "<<l1[i]<<" ";
}
cout<<endl;
return 0;
}
A. compilation error due to line 16
B. program displays 4 4 3 3 2 2 1 1 0 0 0 0 1 1 2 2 3 3 4 4
C. compilation error due to line 11
D. compilation error due to line 12
E. runtime exception
正解：A

質問 4：
What happens when you attempt to compile and run the following code?
#include <vector>
#include <iostream>
using namespace std;
class A
{
int a,b;
public:
A & operator =(const A & c) { a = c.a; return *this;}
A():a(0),b(0){}
void setA(int a) {this?>a = a;} void setB(int b) {this?>b = b;}
int getA() {return a;} int getB() {return b;}
};
int main ()
{
vector<A>v;
A a;
a.setA(10); a.setB(11);
v.push_back(a);
A b = v.front(); v.pop_back();
cout<<b.getB()<<" "<<b.getA()<<endl;
return 0;
}
A. program outputs 11 0
B. compilation error
C. program outputs 10 0
D. program outputs 11 10
E. program outputs 0 10
正解：D

質問 5：
What happens when you attempt to compile and run the following code?
# include <deque>
# include <iostream>
# include <algorithm>
using namespace std;
class B { int val;
public:
B(int v):val(v){} B(){}
int getV() const {return val;} };
ostream & operator <<(ostream & out, const B & v) { out<<v.getV(); return out;} template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) { out<<val<<" "; } };
int main() {
int t[]={8, 10, 5, 1, 4, 6, 2, 7, 9, 3};
deque<B> d1(t, t+10);
deque<B>::iterator it = lower_bound(d1.begin(), d1.end(), 4);
for_each(it, d1.end(), Out<B>(cout));cout<<endl;
return 0;
}
Program outputs:
A. compilation error
B. 4 5 6 7 8 9 10
C. 8 10 5 1 4 6 2 7 9 3
D. 1 2 3 4
E. 1 2 3 4 5 6 7 8 9 10
正解：A

質問 6：
What happens when you attempt to compile and run the following code?
# include <vector>
# include <iostream>
# include <algorithm>
using namespace std;
class B { int val;
public:
B(int v):val(v){}
int getV() const {return val;} bool operator > (const B & v) const { return val>v.val;} }; ostream & operator <<(ostream & out, const B & v) { out<<v.getV(); return out;} template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) { out<<val<<" "; } };
int main() {
B t[]={3,2,4,1,5,10,9,7,8,6};
vector<B> v1(t,t+10);
sort(v1.begin(), v1.end(), greater<B>());
cout<<*min_element(v1.begin(), v1.end());
return 0;
}
Program outputs:
A. 3
B. compilation error
C. 10
D. 6
E. 1
正解：B