C++ miscellaneous MCQ question and answer with solution | C++ Programimg MCQs

#include <iostream>
#include <map>
using namespace std;
int main ()
{
    map<char, int> mymap;
    map<char, int> :: iterator it;
    mymap['b'] = 100;
    mymap['a'] = 200;
    mymap['c'] = 300;
    for (map<char, int> :: iterator it = mymap.begin(); it != mymap.end(); ++it)
        cout << it -> first << " => " << it -> second << '\n';
    return 0;
}

#include <iostream>
#include <deque> 
using namespace std;
int main ()
{
    unsigned int i;
    deque<int> mydeque;
    deque<int> :: iterator it;
    mydeque.push_back ( 100 );
    mydeque.push_back ( 200 );
    mydeque.push_back ( 300 );
    for (it = mydeque.begin(); it != mydeque.end(); ++it)
        mydeque.clear();
    cout << ' ' << *it;
}

#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};
    vector<int> myvector (myints, myints + 4);
    partial_sort (myvector.begin(), myvector.begin() + 2, 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;
}

#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	cout<<sin(cn)<<endl;
	return 0;
}

#include <iostream> 
#include <limits>
using namespace std;
int main( )
{
    cout << numeric_limits<float> :: digits10 << endl;
    cout << numeric_limits<double> :: digits10 << endl;
    float f = 99999999;
    cout.precision ( 10 );
    cout << f << endl;
}