Chapter 4, Problem 1P

Explanation of Solution

Program code:

//include the required header files

#include <iostream>

#include<time.h>

//use the std namespace

using namespace std;

//Declare n as type of constant

const int n = 10;

//Implementation of prefixAverages1 array

double *prefixAverages1(int X[])

{

//Declare a as integer type

int a;

//Decalre A as double pointer type array

double *A = new double[n];

//Iterate the loop

for (int i = 0; i <= n - 1; i++)

{

//assign 0 to a

a = 0;

//Iterate the loop

for (int j = 0; j <= i; j++)

{

//calculate a = a+X[j] value

a = a + X[j];

}

//assign a / (i + 1)

A[i] = a / (i + 1);

}

//return value of the array A

return A;

}

//Implementation of prefixAverages1 array

double *prefixAverages2(int X[])

{

//Declare s and assign 0

int s = 0;

//Decalre A as double pointer type array

double *A = new double[n];

//Iterate the loop

for (int i = 0; i <= n - 1; i++)

{

//calculate s = s+X[i] value

s = s + X[i];

//assign s / (i + 1)

A[i] = s / (i + 1);

}

//return A

    return A;

}

int main()

{

//Decalre X as type of an array

int X[n];

//Declare differenceValue1, differenceValue2 as type of double

double differenceValue1, differenceValue2;

//Declare timeInseconds1, timeInseconds2 as type of double

double timeInseconds1, timeInseconds2;

//Declare i as type of integer

int i = 0;

//Iterate the loop

while (i <= n)

{

//assign i to X[i]

X[i] = i;

//increment i

i++;

}

//Declare resultimeEntrie1,resultimeEntrie2 as type of double

double *resultimeEntrie1 =0, *resultimeEntrie2 = 0;

// declare clock_t objects as timeEntrie1,timeEntrie2

clock_t timeEntrie1, timeEntrie2;

timeEntrie1 = clock();

//store the return value of prefixAverages1(x)

resultimeEntrie1 = prefixAverages1(X);

//Declare k as integer type and assign 0

int k = 0;

// initialize timeEntrie2

timeEntrie2 = clock();

// get the differenceValueerence of two object values

differenceValue1 = (double)timeEntrie2 - (double)timeEntrie1;

// calculate timeInseconds

timeInseconds1 = differenceValue1 / CLOCKS_PER_SEC;

// display statement for timeInseconds

cout << " prefixAverages1(X) " << endl;

//Display statement

cout<<"For n = " << n << " elements then it take " << timeInseconds1 << " seconds" << endl;

// declare clock_t objects as timeEntrie3,timeEntrie4

clock_t timeEntrie3, timeEntrie4;

timeEntrie3 = clock();

//store the return value of prefixAverages2(x)

resultimeEntrie2 = prefixAverages2(X);

timeEntrie4 = clock();

// calculate the differenceValue of two object values

differenceValue2 = (double)timeEntrie4 - (double)timeEntrie3;

// calculate timeInseconds

timeInseconds2 = differenceValue2 / CLOCKS_PER_SEC;

// display statement for timeInseconds

cout << " prefixAverages2(X)" << endl;

//Display statement

cout<<"\n For n = " << n << " elements then it take " << timeInseconds2 << " seconds" << endl;

    return 0;

}

Explanation:

The above program snippet is used to implement “prefixAverages1()” and “prefixAverages2()”. In the code,

• Include the required header files.
• Use the “std” namespace.
• Declare the constant “n”.
• Define the method “prefixAverages1()”.
  • Declare the required variables.
  • Declare an array “A”.
  • Iterate a “for” loop.
    • Calculate the value of “a”.
    • Iterate a “for” loop.
      • Calculate the value of “a”.
    • Assign a value “a/(i+1)”.
  • Return the value of “A”...