Question

How do i change the vector v to size 20 in C++.

Also given the following, which line of code stores 40 into the 4th column of the 6th row of array dataVals?

const int rows = 7;
const int cols = 5;
int dataVals[rows][cols];

Select one:

a. dataVals[5, 3] = 40;

b. dataVals[5 * 3] = 40;

c. dataVals[3][5] = 40;

d. dataVals[5][3] = 40;

Answer 1

1. To increase the Size of vector in C++ , twn method can use .
[1] resize();
   The resize() method (and passing argument to constructor is equivalent to that) will insert or delete appropriate number of elements to the vector to make it given size (it has optional second argument to specify their value).
    It will affect the size(), iteration will go over all those elements, push_back will insert after them and you can directly access them using the operator[].
[2] reverse();
   method only allocates memory, but leaves it uninitialized. It only affects capacity(), but size() will be unchanged. There is no value for the objects, because nothing is added to the vector.
   If you then insert the elements, no reallocation will happen, because it was done in advance, but that's the only effect.

2. Array Will start From [0][0] and end with [n-1][m-1] for dataVals[n][m]
    So [D] dataVals[5][3] = 40 Correct Answer