C++ Institute CPP 問題集

質問 1：
What will happen when you attempt to compile and run the code below, assuming that you enter the following sequence: one two three<enter>?
# include <iostream>
# include <string>
using namespace std;
int main ()
{
string a;
cin.getline(a);
cout<<a<<endl;
return 0;
}
Program will output:
A. compilation error
B. one two three
C. the result is unspecified
D. runtime exception
E. one
正解：A

質問 2：
What happens when you attempt to compile and run the following code?
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
using namespace std;
int main() {
int t[] = {1,2,3,2,3,5,1,2,7,3,2,1,10, 4,4,5};
vector<int> v1(t, t + 15);
set<int> s1(t, t + 15);
pair<set<int>::iterator, vector<int>::iterator > resultSet = mismatch(s1.begin(), s1.end(), v1.begin());
cout<<*resultSet.first<<" "<<*resultSet.second<<endl;
return 0;
}
Program outputs:
A. 4 2
B. 0 5
C. compilation error
D. 2 4
正解：A

質問 3：
What happens when you attempt to compile and run the following code?
# include <vector>
# include <iostream>
# include <algorithm>
using namespace std;
template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) { out<<val<<" "; } };
int main() {
int t1[]={3,2,4,1,5};
int t2[]={5,6,8,2,1};
vector<int> v1(10);
sort(t1, t1+5);
sort(t2, t2+5);
set_symmetric_difference(t1,t1+5,t2,t2+5,v1.begin());
for_each(v1.begin(), v1.end(), Out<int>(cout));cout<<endl;
return 0;
}
Program outputs:
A. 6 8 3 4 0 0 0 0 0 0
B. compilation error
C. 6 8 0 0 0 0 0 0 0 0
D. 3 4 0 0 0 0 0 0 0 0
E. 3 4 6 8 0 0 0 0 0 0
正解：E

質問 4：
What happens when you attempt to compile and run the following code? Choose all that apply.
# include <iostream>
# include <fstream>
# include <string>
# include <list>
# include <algorithm>
#include <iomanip>
using namespace std;
template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) {out<<setw(3)<<hex<<val; } };
int main () {
int t[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
fstream f("test.out", ios::trunc|ios::out);
list<int> l(t, t+10);
for_each(l.begin(), l.end(), Out<int>(f));
f.close(); f.open("test.out");
for( ; f.good() ; ) {
int i; f>>i;
cout<<i<<" ";
}
f.close();
return 0;
}
A. file test.out will be truncated
B. file test.out will be opened writing
C. no file will be created nor opened
D. file test.out will be opened for reading
E. program will display sequence 1 2 3 4 5 6 7 8 9 10
正解：A,B,D,E

質問 5：
What happens when you attempt to compile and run the following code?
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
using namespace std;
void myfunction(int i) {
cout << " " << i;
}
int main() {
int t[] = { 10, 5, 9, 6, 2, 4, 7, 8, 3, 1 };
set<int> s1(t, t+10);
vector<int> v1(s1.rbegin(), s1.rend());
swap(s1, v1);
for_each(v1.begin(), v1.end(), myfunction);
for_each(s1.begin(), s1.end(), myfunction);
return 0;
}
Program outputs:
A. 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10
B. compilation error
C. 10 9 8 7 6 5 4 3 2 1 10 9 8 7 6 5 4 3 2 1
D. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
正解：B

質問 6：
What will happen when you attempt to compile and run the code below, assuming that you enter the following sequence: 1.1 2.2 3.3<enter>?
# include <iostream>
# include <string>
using namespace std;
int main ()
{
int a,b,c;
cin>>a>>b>>c;
cout<<a<<b<<c<<endl;
return 0;
}
Program will output:
A. 123
B. none of these
C. 1.1 2.2 3.3
D. 1.12.23.3
E. 1 2 3
正解：B