Question

This C++ Programs should be written in Visual studio 2017

PROGRAM 1: Comparing Using Arrays to Using Individual Variables

One of the main advantages of using arrays instead of individual variables to store values is that the program code becomes much smaller. Write two versions of a program, one using arrays to hold the input values, and one using individual variables to hold the input values. The programs should ask the user to enter 10 integer values, and then it should write out their total.

Submit both versions of the program with this lab along with their test output. Write a short paragraph describing your observations about writing a program like this using individual variables versus using arrays.

PROGRAM 2: Working with Input Using Arrays

Write a program to read in a sequence of up to ten integers terminated with the sentinel value -1 and to store them in an integer array. The -1 value should not be stored in the array. The number of values read (not including the sentinel) should be kept in a separate variable. This is similar to the examples in the notes using the scores array, MAXCLASS, and numScores.

After the user has entered the numbers, the program should show how many numbers were entered, the total of the values, the average of the values, the number of values greater than the average, and the numbers in the reverse order of their entry. Here is an example of how the program might look when run (user input highlighted):

                Enter number: 4

                Enter number: 2

                Enter number: 6

                Enter number: -1

3 numbers were read in.

       The total is 12.

       The average is: 4.00

       Number of values greater than the average: 1

Values in reverse order: 6 2 4

Test the program on lists of length 0, 1, 5 and 10. Submit the source code and copies of the screen dialogue between the user and the program for each test run.

PROGRAM 3: Collecting String Input Values Using Arrays

Arrays can hold string values as well as numeric values. Write a program to read in a sequence of up to ten names from the user, storing each of them into an array of string. The input should be terminated by the user entering “***END***” instead of a name. After the names have been read in, the program should write them out to the screen.

Use a for loop that counts down from numValues-1 to 0, to write out the list in reverse order.

One of the issues with using the cin instruction to read strings is that it will only not read in strings that contain a space. For example, suppose you have the following code:

string name; cin >> name;

If the user enters a name with a space, like “Hugh Jackman”, only “Hugh” will be entered into the name variable. The “Jackman” part of the input will be saved into an input buffer, and if the program uses cin to read another name, the user will not be given the chance to type anything. Instead, the value “Jackman” that is left over from the first entry will be entered instead.

If you want to be able to read strings that contain spaces, you must use the getline() function, which is part of the iostream library. Here is an example of how to use this function:

string name; getline(cin, name);

When the program uses getline(), the user can enter a line of text that may contain spaces. The entire line will be stored into the variable (in this case, name).

Here is an example of what this program might look like when it is executed (user input highlighted):

                Enter a name: Hugh Jackman

                Enter a name: Jennifer Lawrence

                Enter a name: Michael B. Jordan

              Enter a name: ***END***

       You entered:

       Hugh Jackman

       Jennifer Lawrence

       Michael B. Jordan

Test your program with 0, 3, and 10 names to make sure it works.

PROGRAM 4: Simple Statistics

Write a program that will read in up to 10 numbers, ending with -1. After the numbers have been read in, your program should compute and display their mean and variance. Recall the definitions of mean and variance:

Mean:                    Add up all the numbers and divide by how many there are. This is usually called the “average”.

Variance:              The variance is obtained by adding together the squares of the differences of each element and the mean.                     This total is then divided by the number of elements. So, if the numbers were in X[0] through X[6]:

variance = ((X[0]-mean)²+(X[1]-mean)²+...+(X[6]-mean)²) / 7.

Here is an example of what the program might look like (user input highlighted):

Enter number 1 (-1 to end): 1

Enter number 2 (-1 to end): 3

Enter number 3 (-1 to end): 5

Enter number 4 (-1 to end): -1

The mean is: 3

The variance is: 2.66667         Test this program several times on lists of different lengths.

Note: this lab is about using arrays, and not about functions. Do not use functions to write this program

Answer 1

In this answer, we have implemented the solutions to the four problems, which highlights the use of arrays. Arrays help us in storing and accessing data easier and faster as compared to storing values in individual variables, for e.g, if we had to store data of 1000 names then it would be really difficult to create 1000 variables first and then take their values, whereas an array just has to run a loop with one same command. Below are the solutions:

Solution 1a:

Code:

#include <iostream>

using namespace std;

int main() {

    //Prompt user for the input
    cout << "Enter 10 integer values: " << endl;
    int size = 10;
    int array[size];
    int sum = 0;
    //Take input
    for (int i = 0; i < size; i++) {
        cin >> array[i];
        sum += array[i];
    }

    cout << "The sum is: " << sum << endl;

    return 0;
}

#include <iostream> using namespace std; int main() { //Prompt user for the input cout << "Enter 10 integer values: " << endl; int size = 10; int array[size]; int sum = 0; //Take input for (int i = 0; i < size; i++) { cin >> array[i]; sum += array[i]; } cout << "The sum is: " << sum << endl; return; }

Output:

Enter 10 integer values: 1 2 3 4 5 6 7 8 9 10 The sum is: 55 Process returned 0 (0x0) Press any key to continue. execution time : 4.949 s

Solution 1b:

Code:

#include <iostream>

using namespace std;

int main() {

    //Prompt user for the input
    cout << "Enter 10 integer values: " << endl;
    int size = 10;
    int one, two, three, four, five, six, seven, eight, nine, ten;
    int sum = 0;
    //Take input
    cin >> one >> two >> three >> four >> five >> six >> seven >> eight >> nine >> ten;

    sum += one + two + three + four + five + six + seven + eight + nine + ten;
    cout << "The sum is: " << sum << endl;

    return 0;
}

#include <iostream> using namespace std; int main() { //Prompt user for the input cout << "Enter 10 integer values: " << endl; int size = 10; int one, two, three, four, five, six, seven, eight, nine, ten; int sum = 0; //Take input cin >> one >> two >> three >> four >> five >> six >> seven >> eight >> nine >> ten; sum += one + two + three + four + five + six + seven + eight + nine + ten; cout << "The sum is: " << sum << endl; return 0;

Output:

Enter 10 integer values: 1 2 3 4 5 6 7 8 9 10 The sum is: 55 Process returned 0 (0x0) Press any key to continue. execution time : 4.949 s

Solution 2:

Code:

#include <iostream>
using namespace std;

int main() {

    //Prompt user for the input
    int size = 10;
    int array[size];
    double sum = 0;
    double average;
    int count = 0;
    //Take input
    for (int i = 0; i < size; i++) {
        cout << "Enter number: ";
        int num;
        cin >> num;
        if (num == -1) {
            break;
        } else {
            array[i] = num;
            sum += array[i];
            count++;
        }
    }

    average = sum / count;
    int greater = 0;
    for (int i = 0; i < count; i++) {
        if (array[i] > average) {
            greater++;
        }
    }
    cout << count << " numbers were read in." << endl;
    cout << "The total is: " << sum << endl;
    printf("The average is: %.2f\n", average);
    cout << "Number of values greater than the average: " << greater << endl;
    cout << "Values in reverse order: ";
    for (int i = count - 1; i >= 0; i--) {
        cout << array[i] << " ";
    }
    cout << endl;
    return 0;
}

#include <iostream> using namespace std; 2 3 4 Hint main() { 5 6 2 8 9 11 12 o 13 14 15 //Prompt user for the input int size = 10; int array[size]; double sum = 0; double average; int count = 0; //Take input for (int i = 0; i < size; i++) { cout << "Enter number: "; int num; cin >> num; if (num -1) { break; } else { array[i] = num; sum += array[i]; count++; 16 18 19 20 21 22 23 24 e } 25 26 27 28 D-D 29 30 31 32 33 34 average = sum / count; int greater = 0; for (int i = 0; i < count; i++) { if (array[i] > average) { greater++; } } cout << count << "numbers were read in." << endl; cout << "The total is: " << sum << endl; printf("The average is: %.2f\n", average); cout << "Number of values greater than the average: cout << "Values in reverse order: "; for (int i = count 1; i >= 0; i--) { cout << array[i] << "."; } cout << ; return 0; 35 36 << greater << endl; 37 1:38 39 40 41 42 43

Output:

Enter number: 4 Enter number: 2 Enter number: 6 Enter number: -1 3 numbers were read in. The total is: 12 The average is: 4.00 Number of values greater than the average: 1 Values in reverse order: 6 2 4 Process returned 0 (0x0) execution time : 15.446 s Press any key to continue.

Solution 3:

Code:

#include <iostream>

using namespace std;

int main() {

    //Prompt user for the input
    int size = 10;
    string names[size];
    int numValues = 0;
    //Take input
    for (int i = 0; i < size; i++) {
        cout<< "Enter a name: ";
        string name;
        getline(cin, name);

        //If terminating string is entered, quit
        if (name.compare("***END***") == 0) {
            break;
        } else {
            names[i] = name;
            numValues++;
        }
    }

    cout << "You entered: " << endl;
    for (int i = 0; i < numValues; i++) {
        cout << names[i] << endl;
    }


    return 0;
}


1 #include <iostream> 2 3 using namespace std; 4 5 Fint main() { ö 7 8 9 10 11 //Prompt user for the input int size = 10; string names[size]; int numValues = 0; //Take input for (int i = 0; i < size; i++) { cout<<"Enter a name: "; string name; getline(&: cin, &: name); 12 13 14 15 16 18 D 19 //If terminating string is entered, quit if (name.compare( s: "***END***") == 0) { break; } else { names[i] = name; numValues++; 20 21 22 23 A 24 } } 25 26 27 U cout << "You entered: " << endl; for (int i = 0; i < numValues; i++) { cout << names[i] << endl; } 28 29 30 31 32 return 0; 33 } 34

Output:

Enter a name: Hugh Jackman Enter a name: Jennifer Lawrence Enter a name: Micheal B. Jordan Enter a name: ***END*** You entered: Hugh Jackman Jennifer Lawrence Micheal B. Jordan Process returned 0 (0x0) execution time : 44.874 s Press any key to continue.

Solution 4:

Code:

#include <iostream>
using namespace std;

int main() {

    //Prompt user for the input
    int size = 10;
    int array[size];
    double sum = 0;
    double mean;
    int count = 0;
    //Take input
    for (int i = 0; i < size; i++) {
        cout << "Enter number " << (i + 1) << " (-1 to end): ";
        int num;
        cin >> num;
        if (num == -1) {
            break;
        } else {
            array[i] = num;
            sum += array[i];
            count++;
        }
    }

    //Calculate mean and variance
    mean = sum / count;
    double variance;
    for(int i =0;i<count;i++){
        variance += (array[i] - mean) * (array[i] - mean);
    }

    variance /= count;

    cout<<"The mean is: "<<mean<<endl;
    cout<<"The variance is: "<<variance<<endl;

    return 0;
}


1 #include <iostream> using namespace std; 2 3 4 eint main() { 5 6 8 10 12 13 //Prompt user for the input int size = 10; int array[size]; double sum = 0; double mean; int count = 0; //Take input for (int i = 0; i < size; i++) { cout << "Enter number " << (i + 1) << " (-1 to end): "; int num; cin >> num; if (num -1) { break; } else { array[i] = num; sum += array[i]; count++; 15 16 17 18 19 20 21 22 23 24 } 25 26 27 28 //Calculate mean and variance mean = sum / count; double variance; for(int i =0;i<count;i++){ variance += (array[i] - mean) * (array[i] - mean); } 29 30 31 32 33 variance /= count; 34 35 cout<<"The mean is: "<<mean<<endl; cout<<"The variance is: "<<variance<<endl; 36 37 38 return 0; 39 } 140

Output:

Enter number 1 (-1 to end): 1 Enter number 2 (-1 to end): 3 Enter number 3 (-1 to end): 5 Enter number 4 (-1 to end): -1 The mean is: 3 The variance is: 2.66667 Process returned 0 (0x0) execution time: 4.537 s Press any key to continue.