Question 12 Lines Produced Following Code Assuming Correctly Implemented Program May Need Q23153909

QUESTION 12

Which of these lines is NOT produced by the following code,assuming they are correctly implemented in a program?
(You may need to fix them, but without altering the output, i.e.fix the double quotes)

cout << “*” << setw(5) << 123 <<“*”
<< 123 << “*” << endl;
cout.setf(ios::showpos);
cout << “*” << setw(5) << 123 << “*”
<< 123 << “*” << endl;
cout.unsetf(ios::showpos);
cout.setf(ios::left);
cout << “*” << setw(5) << 123 << “*”
<< setw(5) << 123 << “*” << endl;

*123**

+123*+123*

123*123*

*123 *

10 points   

QUESTION 13

Which of the following are correct ways to end a loop using atest for end-of-file?

(Two correct answers)

inStream.get(next);
while(!inStream.eof( ))
{
cout << next;
inStream.get(next);
}

inStream.get(next)
while(!eof(inStream))
{
cout << next;
inStream.get(next);
}

while(inStream >> next)
  cout << next;

while(inStream->next)
  {
cout << next;
}

10 points   

QUESTION 14

Which function takes a single char value from the input file,without regard to whether it is a whitespace?

putline()

getline()

get()

put()

10 points   

QUESTION 15

To open a file for read-write and random access does NOTrequire

#include, using std::fstream; and using std::ios;

The stream to be defined using the class fstream. defined in theheader file

The usual definition of an ofstream or ifstream object

The stream to be connected to the physical file object withfirst argument a C-string containing the physical file name and asecond argument, ios::in | ios::out that specifies that the i/owith the file should be for either reading or writing

10 points   

QUESTION 16

Why does this version of the swap function fail to work? Isthere a fix?
void swap(int & lhs, int& rhs)
{
lhs = rhs;
rhs = lhs;
}

We can fix if we just reverse the order of the lines.

It works OK.

It fails because the programmer forgot to make the parameterscall-by-reference

It fails because the first line destroys the old value of lhswithout saving it. Then both variables have the old value of rhs inthem.

10 points   

QUESTION 17

Consider the following function and code segment.
void One( int first, int & second )
{
first = 17;
second = first + 1;
}
int main()
{
// other code …
int j = 4;
int k = 3;
One(j, k);
// other code ..
}
After the call to One(j, k); what are the values of j and k?

j == 17, k == 18;

j == 4, k == 3;

j == 4, k == 18;

j == 17, k == 3;

10 points   

QUESTION 18

Which is correct?

There is only one kind of parameter passing in C++, namelycall-by-value

The call-by-reference mechanism is specified in the functiondeclaration and definition, using a $ between the type and theparameter

The position of the ampersand in the function header is of noimportance to the proper compiling and execution of code that usescall-by-reference parameters

A call-by-reference parameter may pass data only out of afunction

10 points   

QUESTION 19

Which is correct?

Names of parameters in functions, especially functionprototypes, have no meaning, and may be selected quitearbitrarily.

The compiler ha no problem distinguishing these two functiondefinitions:
void func(double &x){/*…*/}
void func(double x){/*…*/}

Call-by-reference is restricted to void functions

There is no problem with the compiler distinguishing these twofunction definitions:
void func(double x){/*…*/}
int func(double x){/*…*/ return something_double;}

10 points   

QUESTION 20

Consider the function, where the programmer inadvertently leftout the ampersand in the definition of parRef. What is the outputof the code?
void doStuff(int parValue, int parRef)
{
parValue = 100;
cout << “parValue in call to doStuff = “
<< parValue << endl;
parRef =222;
cout << “parRef in call to doStuff = “
<< parRef << endl;
}
and consider the call, which we assume is in a complete and correctprogram
int n1 = 1, n2 =2;
doStuff(n1, n2);
cout << “n1 after call to doStuff = “ << n1 <<endl;
cout << “n2 after call to doStuff = “ << n2 <<endl;

parValue in the call to doStuff = 100;
parValue in the call to doStuff = 222;
n1 after function call = 1;
n2 after function call = 222

parValue in the call to doStuff = 100;
parValue in the call to doStuff = 222;
n1 after function call = 100
n2 after function call = 222

parValue in the call to doStuff = 100;
parValue in the call to doStuff = 222;
n1 after function call = 1;
n2 after function call = 2

x parValue in the call to doStuff = 100;
parValue in the call to doStuff = 222;
n1 after function call = 100
n2 after function call = 2

QUESTION 9

Which of the following is a restriction on use of a streamvariable (either ifstream or ofstream)?

To use a stream variable as a function parameter you can onlyuse call-by-reference

To use a stream variable as a function parameter you can onlyuse call-by-value

To use a stream variable as a function parameter you can usecall-by-value or call-by-value

A file variable can be used in any way any other variable can beuse

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