The answers are in red. Please explain the answer using C++ logic Use the follow

Question

  The answers are in red. Please explain the answer using C++ logic

Use the following function definition for the next 2 questions

void swap( int &a, int &b )

{

int temp = a;

a = b;

b = temp;

}

7. Which of the following statements correctly calls the swap

function defined above to swap the values at the front and back of a vector of integers named v?

(Assume v stores at least 2 integers.)

a. swap(0, v.size());

b. v.swap(0, v.size());

c. v[0] = v[v.size()];

d. swap(v[1], v[v.size()]);

e. swap(v[0], v[v.size() - 1]);

f. swap(v, v.size() - 1);

8. Assuming an integer variable named x has been declared and initialized to a

positive value less than 10, which of the following statements correctly calls the

swap function defined above to swap the values at index x of a vector integers named  v with the value in v stored immediately after index x?

(Assume v has a size of at least 20.)

a. swap(x, x + 1);

b. v.swap(x, x + 1);

c. v[x] = v[x] + 1;

d. swap(v[x], v[x + 1]);

e. swap(v[x], v[x] + 1);

f. swap(v + x, v + x + 1);

9. Assuming v is a vector of integers and n is a variable of type int that have been

declared and initialized with positive integers, which of the following statements has a

syntax  error?

a. vector v1(n);

b. vector v2 = v;

c. v[n] = 10;

d. v[10] = n;

e. cout << v[n] + n;

f. cout << v;

Explanation / Answer

in order to swap the contents of vector u have to pass contents of vector.

only in option e you are sending contents of vector

swap(v[0],v[v.size()-1]) is correct choice.

to swap values at location index u have pass vector value at that location and ...

d. swap(v[x], v[x + 1]);   is correct choice.

v is Vector of integers

u cant print by statement cout << v;

which is a syntax error.

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