Question

I have to type and explain in class each code in every detail filled with // commentary.

Explains how does work in every codes.

1)

What does the below print

#include <iostream>
using namespace std ;

int main()
{

   int var1 = 20 ;
   int var2 = 30 ;

   int* ptr1 ;
   int* ptr2 ;
   int* temp ;


   ptr1 = &var1 ;
   ptr2 = &var2 ;

   cout << *ptr1 << endl ;
   cout << var2 << endl ;
   cout << *ptr2 << endl ;

   temp = ptr1 ; ptr1 = ptr2 ;
   ptr2 = temp ;

   cout << *ptr1 << endl ;
   cout << var1 << endl ;
   cout << *ptr2 << endl ;
}

2)

What does the below print ?

#include <iostream>

using namespace std ;




int main()
{

int arr1[2][3] = { {1,2,3} , { 4,5,6}    } ;

for( int i1=0 ; i1<3 ; i1++ )
   {
     arr1[0][i1] = arr1[0][i1] + 1 ;
     arr1[1][i1] = arr1[1][i1] - 1 ;

   }

for( int i1=0 ; i1<2 ; i1++ )
   {
     for( int i2=0 ; i2<3 ; i2 = i2 +2 )
       {
          cout << arr1[i1][i2] << " " ;
       } //for
     cout << endl ;

   } //for



}

3)

What does the following print ?

#include <iostream>

using namespace std ;


void showLocal()
{
static int localNum = 5 ;

cout << "localNum is " << localNum << endl;
localNum++ ;
}


void showLocalOne()
{
int localNum = 5 ;

cout << "localNum in showLocalOne is " << localNum << endl;
localNum++ ;
}



int main()
{
   showLocal();
   showLocal();

   showLocalOne();
   showLocalOne();



   return 0;
}

4)

The following program uses linear search to search a particular section of an array. What will it print ?

#include <iostream>

using namespace std ;


int searchList( const int list[], int size, int value, int leftIndex, int rightIndex )
{
   int index = 0;        // Used as a subscript to search array
   int position = -1;    // To record position of search value
   bool found = false;   // Flag to indicate if the value was found


   for( int i1=leftIndex ; i1<= rightIndex ; i1++ )
   {
    cout << list[i1] << " : " ;
      if (list[i1] == value)   // If the value is found
      {
        cout << list[i1] << " : " ;
        return ( i1 ) ;
      }
                         // Go to the next element
   }
   return position;               // Return the position, or -1
}



int main()
{
    int arr1[] = { 5 , 2 , 1 , 9 , 3 , 4 } ;

    searchList (   arr1 , 6, 3 , 2, 4 ) ;
    cout << endl ;

    searchList (   arr1 , 6, 3 , 1, 3 ) ;
    cout << endl ;
    searchList (   arr1 , 6, 10 , 1, 3 ) ;
    cout << endl ;

    return ( 0 ) ;
}

5)

What does the following print ?

#include <iostream>

using namespace std ;


int binarySearch(const int array[], int numElems, int value)
{
    int first = 0,   // First array element
        last = numElems - 1,   // Last array element
        middle,   // Midpoint of search
        position = -1;   // Position of search value
    bool found = false;   // Flag

    while (!found && first <= last)
    {
        middle = (first + last) / 2;   // Calculate midpoint
        cout << array[middle] << " : " ;
        if (array[middle] == value)   // If value is found at mid
        {
           found = true;
           position = middle;
        }
        else if (array[middle] > value) // If value is in lower half
           last = middle - 1;
        else
           first = middle + 1;   // If value is in upper half
    }

    cout << position << " : " ;
    return position;
}




int main()
{
    int arr1[] = { 1 , 2 , 3 , 4 , 6 , 9 } ;

    binarySearch(    arr1 , 6, 3   ) ;
    cout << endl ;

    binarySearch(    arr1 , 6, 5 ) ;
    cout << endl ;
    binarySearch(    arr1 , 6, 1 ) ;
    cout << endl ;

    return ( 0 ) ;
}

6)

What does the following program print ?

#include <iostream>

using namespace std ;

void printArray( int array1[], int size )
{
for( int i1=0 ; i1<size ; i1++ )
    {
       cout << array1[i1] << " " ;

    }
cout << endl ;

}

void selectionSort( int array[], int size )
{
    int startScan, minIndex, minValue;
    for (startScan = 0; startScan < (size - 1); startScan++)
    {
        minIndex = startScan;
        minValue = array[startScan];
        for(int index = startScan + 1; index < size; index++)
        {
            if (array[index] < minValue)
            {
                minValue = array[index];
                minIndex = index;
            }
        }

        array[minIndex] = array[startScan];
        array[startScan] = minValue;
        printArray( array , size ) ;
    }
}






int main()
{
    int arr1[] = { 5 , 8 , 2 , 7 } ;

    selectionSort(    arr1 , 4 ) ;
    cout << endl ;

    return ( 0 ) ;
}

7)

#include <iostream>
#include <cstring>

using namespace std ;







int main()
{
    char ch1 = 'a' ;
    char buffer[256] ;

    cout << char( toupper( ch1 ) ) << endl ;
    cout << char( toupper( ch1 + 1 ) ) << endl ;
    cout << char( tolower( ch1 + 2 ) ) << endl ;

    strcpy ( buffer, "Henry " ) ;
    strcat ( buffer , "Armstrong" ) ;

    cout << strlen( buffer ) << " : " <<
        buffer << endl ;


    return ( 0 ) ;
}

8)

What does the following print ?

#include <iostream>
#include <cstring>

using namespace std ;



int main()
{
    int arr1[] = { 10 , 20, 30, 40 } ;
    int* ptr1 ;
    int index = 0 ;

    ptr1 = arr1 ;
    index++ ;

    cout << *( ptr1 + ++index ) << endl ;
    cout << *( arr1 + ++index ) << endl ;
    cout << arr1[--index] << endl ;
    cout << ptr1[--index] << endl ;


    return ( 0 ) ;
}

9)

What does the following print ?

#include <string>
#include <iostream>

using namespace std;

struct EmployeePay
{
string name;       // Employee name
int empNum;       // Employee number
double payRate;    // Hourly pay rate
double hours;      // Hours worked
double grossPay;    // Gross pay
};

void print( EmployeePay emp )
{
cout << emp.name << " : " << emp.empNum << " : " <<
    emp.payRate << " : " << emp.hours << " : " << emp.grossPay <<
    endl ;

}

int main()
{
EmployeePay employee1 = {"Betty Ross", 1, 18.75   }   ;
EmployeePay employee2 = {"Jill Sandburg", 2, 40, 10 , 400   } ;

print( employee1 ) ;
print( employee2 ) ;
}

10)

What will the following print ?

#include <iostream>

using namespace std ;


class Demo
{
public:
int x1 ; int x2 ;

Demo(int x1p, int x2p)
{
   x1 = x1p ;
   x2 = x2p ;
   cout << "Inside the constructor." << endl ;
   cout << "x1:" << x1 << " x2:" << x2 << endl ;
}

   ~Demo()
   {
       cout << "Inside the destructor." << endl ;
       cout << "x1:" << x1 << " x2:" << x2 << endl ;

   }


};


int main()
{
cout << "Before creating the object." << endl ;
Demo demo1Obj ( 2,5 ) ;
cout << "After creating the object." << endl ;

Demo demo2Obj ( 3, 6 ) ;





}

Answer 1

/******************************************************************************

Online C++ Compiler.
Code, Compile, Run and Debug C++ program online.
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*******************************************************************************/

#include <iostream>
using namespace std ;

int main()
{
//variable declarations
int var1 = 20 ;
int var2 = 30 ;
//pointer varaible declaration
int* ptr1 ;
int* ptr2 ;
int* temp ;

ptr1 = &var1 ;//pointing ptr1 to the address of var1
ptr2 = &var2 ;//pointing ptr 2 to the address of var2

cout << *ptr1 << endl ;//prints 20, because ptr1 points to address of var1, and *ptr1 means value at address of var1
cout << var2 << endl ;//prints 30
cout << *ptr2 << endl ;//prints 30

temp = ptr1 ;//now temp points to address of var1
ptr1 = ptr2 ;//ptr1 points to var2
ptr2 = temp ;//ptr2 points to var1

cout << *ptr1 << endl ;//prints 30
cout << var1 << endl ;//prints 20
cout << *ptr2 << endl ;//prints 20
}

Output:

20

30

30

30

20

20

Note: As per Chegg policy, I am allowed to answer only 1 question(including sub-parts)

on a single post, kingly post the remaining questions seperately and i will try to answer them

Sorry for the inconvenience caused, thank you