CPP Online Practice Questions and Answers

What happens when you attempt to compile and run the following code?

#include

#include

using namespace std;

int main() {

int t[] = { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5 };

string s[] = { "one", "one", "two", "two", "three","three", "four", "four", "five", "five"};

map m;

for (int i = 0; i < 10; i++) {

m.push_back(pair(t[i], s[i]));

}

for (map::iterator i = m.begin(); i != m.end(); i++) {

cout << i?>first << " ";

}

return 0;

}

A. program outputs: 1 2 3 4 5

B. compilation error

C. program outputs: 1 1 2 2 3 3 4 4 5 5

D. program outputs: one two three four five

E. program outputs: one one two two three three four four five five

What happens when you attempt to compile and run the following code?

#include

#include

#include

#include

using namespace std;

void myfunction(int i) {

cout << " " << i;

}

bool classifier(int v) {

return v%2==0;

}

int main() {

int t[] = { 1, 5, 2, 5, 2, 4, 4, 3, 3, 1 };

vector v1(t, t+10);

set s1(t, t+10);

replace(v1.begin(), v1.end(),classifier, 10);

for_each(v1.begin(), v1.end(), myfunction);

return 0;

}

Program outputs:

A. 1 5 10 5 10 10 10 3 3 1

B. 1 5 2 5 2 4 4 3 3 1

C. compilation error

D. 10 10 2 10 2 4 4 10 10 10

What happens when you attempt to compile and run the following code?

#include

#include

#include

#include

using namespace std;

templatestruct Out {

ostream and out;

Out(ostream and o): out(o){}

void operator() (const T and val ) { out<

int main() {

int t1[]={1,2,3,4,5,6,7,8,9,10};

int t2[]={1,2,3,4,5,6,7,8,9,10};

vector v1(t1, t1+10);

vector v2(t2, t2+10);

vector v3(10);

transform(v1.begin(), v1.end(), v2.rbegin(), v3.begin(), minus());

for_each(v3.rbegin(), v3.rend(), Out(cout));cout<

return 0;

}

Program outputs:

A. 9 7 5 3 1 ?1 ?3 ?5 ?7 ?9

B. ?1 ?3 ?5 ?7 ?9 9 7 5 3 1

C. 1 3 5 7 9 ?1 ?3 ?5 ?7 ?9

D. 1 3 5 7 9 ?1 ?3 ?5 ?7 ?9

E. ?9 ?7 ?5 ?3 ?1 1 3 5 7 9

What happens when you attempt to compile and run the following code? Choose all that apply.

#include

#include

#include

#include

#include

#include

using namespace std;

templatestruct Out {

ostream and out;

Out(ostream and o): out(o){}

void operator() (const T and val ) {out<

int main () {

int t[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

fstream f("test.out", ios::trunc|ios::out);

list l(t, t+10);

for_each(l.begin(), l.end(), Out(f));

f.close(); f.open("test.out");

for( ; f.good() ; ) {

int i; f>>i;

cout<

}

f.close();

return 0;

}

A. file test.out will be opened writing

B. file test.out will be truncated

C. file test.out will be opened for reading

D. no file will be created nor opened

E. program will display sequence 1 2 3 4 5 6 7 8 9 10

Which keywords can be used to define template type parameters? Choose all possible answers:

A. class

B. typedef

C. typename

D. static

E. volatile

What happens when you attempt to compile and run the following code?

#include

#include

#include

#include

using namespace std;

class B { int val;

public:

B(int v=0):val(v){}

int getV() const {return val;}

B operator +(const B andb )const { return B(val + b.val);} };

ostream and operator <<(ostream and out, const B and v) { out<

templatestruct Out {

ostream and out;

Out(ostream and o): out(o){}

void operator() (const T and val ) { out<

B Add(B a, B b) { return a+b; }

int main() {

int t[]={1,2,3,4,5,6,7,8,9,10};

vector v1(t, t+10);

vector v2(10);

transform(v1.begin(), v1.end(), v2.begin(), bind2nd(ptr_fun(Add),1)); for_each(v2.rbegin(), v2.rend(), Out(cout));cout<

return 0;

}

Program outputs:

A. 1 2 3 4 5 6 7 8 9 10

B. 2 3 4 5 6 7 8 9 10 11

C. 10 9 8 7 6 5 4 3 2 1

D. 11 10 9 8 7 6 5 4 3 2

E. compilation error