How many types of comments are there in C++?

Which of the following is not a valid file mode?

 What is the only function all C programs must contain? 

What will be the output of the following C++ code?

What is the output of the following program?

struct time

{

  int H;

  int M;

  int S;

} time1;

int main()

{

  struct time *p;

  p = &time1;

  p->H = 4;

  p->M = 22;

  p->S = 12;

  printf("%d %d %d", p->H, p->M, p->S);

}

#include <iostream>
using namespace std;

int main () {
 int x = 10;
 int y = 20;
 {
   int x;   // ok, inner scope.
   x = 50;  // sets value to inner x
   y = 50;  // sets value to (outer) y
   cout << "x: " << x << '\n';
   
 }
 cout << "x: " << x << '\n';
 
 return 0;
}

What will be the output of the following C++ code?

#include <iostream>

#include <fstream>

using namespace std;

int main() {

ofstream outfile("test.txt");

for (int n = 0; n < 100; n++) {

outfile << n;

outfile.flush();

}

cout << "Done";

outfile.close();

return 0;

}

What is the output of the following C++ code?

 class complex{ 

 double re; 

 double im; 

 public: 

 complex() : re(0),im(0) {} 

 complex(double n) { re=n,im=n;}; 

 complex(int m,int n) { re=m,im=n;} 

 void print() { cout<<re; cout<<im;} 

 };

 void main(){ 

 complex c3; 

 double i=5; 

 c3 = i; 

 c3.print(); 

 }

#include <iostream>

#include <algorithm>

#include <vector>

using namespace std;

int main ()

{

int first[] = {5, 10, 15, 20, 25};

int second[] = {50, 40, 30, 20, 10};

       vector<int> v(10); 

       vector<int> :: iterator it;

       sort (first, first + 5); 

       sort (second, second + 5); 

       it = set_union (first, first + 5, second, second + 5, v.begin());

cout << int(it - v.begin());

return 0;

}

What will be the output of the following C++ code?

#include <iostream>

#include <algorithm>

#include <vector>

using namespace std;

bool myfunction (int i, int j) { return (i < j); }

int main()

{

int myints[] = {9, 8, 7, 6, 5};

vector<int> myvector(myints, myints + 5);

partial_sort(myvector.begin(), myvector.begin() + 3, myvector.end());

partial_sort(myvector.begin(), myvector.begin() + 2, myvector.end(), myfunction);

for (vector<int>::iterator it = myvector.begin(); it != myvector.end(); ++it)

cout << ' ' << *it;

return 0;

}