C++ Programming Questions and Answers – seq_con Vector Class – 1

This set of C++ Programming Multiple Choice Questions & Answers (MCQs) focuses on “seq_con Vector Class – 1”.

1. What are the vectors?
a) Arrays with dynamic size
b) Arrays with different types of elements
c) Same as array classes
d) Arrays with static size but use template classes
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2. Pick the correct statement.
a) Vectors have dynamic size whereas Array classes have a static size
b) Both vectors and Array classes have a dynamic size
c) Both vectors and Array classes have a static size
d) Vectors have static size whereas Array classes have a dynamic size
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3. Pick the incorrect statement.
a) Vectors have a dynamic size
b) Vectors are placed in contiguous storage
c) Insertion in vectors always takes constant time
d) Vectors insert the element at the end
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4. Which of the following header file is needed to use vectors in your program?
a) <array>
b) <vector>
c) <containers>
d) <stdio>
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5. Which of the following(s) can be used to access the first element of a vector v?
a) v.begin()
b) v.cbegin()
c) v[0]
d) all of the mentioned
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6. Which of the following(s) can be used to access the last element of a vector v?
a) v.end()
b) v.cend()
c) both v.end() and v.cend()
d) vectors do not have a function to access the last element
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7. What is the difference between begin() and cbegin() in vectors?
a) both are same
b) begin() returns iterator to first element and cbegin() returns iterator to last element
c) begin() returns an iterator to first element whereas cbegin() returns constant iterator to first element
d) begin() returns returns first element cbegin() returns void
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8. What is the difference between begin() and rbegin()?
a) both are the same
b) begin() returns an iterator to the first element and rbegin() returns an iterator to an element kept at the end of the vector
c) begin() returns an iterator to first element whereas rbegin() returns constant iterator to first element
d) begin() returns returns first element rbegin() returns void
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9. Which is the following is syntactically correct for vector<int> v?
a) vector <int> :: const_iterator itr = v.rbegin();
b) vector <int> :: reverse_iterator itr = v.begin();
c) vector <int> :: iterator itr = v.begin();
d) vector <int> :: iterator itr = v.cbegin();
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10. What will be the output of the following C++ code?

#include <iostream> 
#include <vector> 
 
using namespace std; 
 
int main() 
{ 
    vector<int> v; 
 
    for (int i = 1; i <= 5; i++) 
        v.push_back(i); 
 
    vector<int> :: const_iterator i;
   	for (i = v.begin(); i != v.end(); ++i) 
        cout << *i << " ";
    cout<<endl;
 
    return 0; 
}

a) 1 2 3 4 5
b) 1 3 5
c) 1 4 5
d) Error
View Answer

$ ./a.out 
1 2 3 4 5

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

#include <iostream> 
#include <vector> 
 
using namespace std; 
 
int main() 
{ 
    vector<int> v; 
 
    for (int i = 1; i <= 5; i++) 
        v.push_back(i); 
 
    vector<int> :: iterator i;
    i = v.begin();
    *i = 3;
   	for (i = v.begin(); i != v.end(); ++i) 
        cout << *i << " ";
    cout<<endl;
 
    return 0; 
}

a) 1 2 3 4 5
b) 3 2 3 4 5
c) 5 4 3 2 1
d) 3 3 3 3 3
View Answer

$ ./a.out 
3 2 3 4 5

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

#include <iostream> 
#include <vector> 
 
using namespace std; 
 
int main() 
{ 
    vector<int> v; 
 
    for (int i = 1; i <= 5; i++) 
        v.push_back(i); 
 
    vector<int> :: const_iterator i;
    i = v.begin();
    *i = 3;
   	for (i = v.begin(); i != v.end(); ++i) 
        cout << *i << " ";
    cout<<endl;
 
    return 0; 
}

a) 1 2 3 4 5
b) 3 2 3 4 5
c) Error
d) Segmentation fault
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13. Which of the following function is used to get the actual number of elements stored in vector?
a) v.size()
b) v.capacity()
c) v.max_size()
d) v.no_of_elements()
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14. Which function is used to get the total capacity of a vector?
a) v.size()
b) v.capacity()
c) v.max_size()
d) v.no_of_elements()
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15. How the size of a vector increases once it is full?
a) Vector increases its capacity one by one
b) Vector doubles its capacity after it is full
c) Vector increases its capacity by half of its previous size
d) Vector increases its capacity by a constant factor
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