Question

1.Given an int variable n that has been initialized to a positive value and, in addition, int variables k and total that have already been declared, use a for loop to compute the sum of the cubes of the first n whole numbers, and store this value in total. Thus if n equals 4, your code should put 1*1*1 + 2*2*2 + 3*3*3 + 4*4*4 into total. Use no variables other than n, k, and total.(c++)

2.Given an int variable n that has been initialized to a positive value and, in addition, int variables k and total that have already been declared, use a while loopto compute the sum of the cubes of the first n counting numbers, and store this value in total. Thus if n equals 4, your code should put 1*1*1 + 2*2*2 + 3*3*3 + 4*4*4 into total. Use no variables other than n, k, and total. Do NOT modify n. (c++)

3.Given an int variable n that has been initialized to a positive value and, in addition, int variables k and total that have already been declared, use a do...whileloop to compute the sum of the cubes of the first n whole numbers, and store this value in total. Thus if n equals 4, your code should put 1*1*1 + 2*2*2 + 3*3*3 + 4*4*4 into total. Use no variables other than n, k, and total.(c++)

4.

Read first a user's given name followed by the user's age from standard input. Then use an ofstream object named outdata to write this information separated by a space into a file called outdata. Assume that this is the extent of the output that this program will do.

Declare any variables that you need.(c++)

5.
Write a program that will predict the size of a population of organisms. The program should ask the user for the starting number of organisms, their average daily population increase (as a percentage, expressed as a fraction in decimal form: for example 0.052 would mean a 5.2% increase each day), and the number of days they will multiply. A loop should display the size of the population for each day.

Input Validation.Do not accept a number less than 2 for the starting size of the population. If the user fails to satisfy this print a line with this message "The starting number of organisms must be at least 2.", display the prompt again and try to read the value. Similarly, do not accept a negative number for average daily population increase, using the message "The average daily population increase must be a positive value." and retrying. Finally, do not accept a number less than 1 for the number of days they will multiply and use the message "The number of days must be at least 1."(c++)

Answer 1

Thanks for the question, Please post 1 question at a time.

I have solved the first 4, Please post question 5 in a separate post.

As per Chegg policy, I am suppose to answer only the first 4 questions.

Here is the code in C++, do comment for any further help.

thank you !

===================================================================

#include<iostream>

#include<fstream> // for wriitng data to file

using namespace std;

int main(){

               

               

                int n=4;

                int k;

                int total;

               

                // Problem 1

                total=0;

                for(k=1;k<=n;k++){

                                total+= k*k*k;

                }

                cout<<"Problem 1 total = "<<total<<endl;

               

               

                //Problem 2

                k=1;

                total=0;

                while(k<=4){

                                total+=k*k*k;

                                k+=1;

                }

                cout<<"Problem 2 total = "<<total<<endl;

               

                //Probem 3

                k=1;

                total=0;

                do{

                                total+=k*k*k;

                                k+=1;

                }while(k<=4);

                cout<<"Problem 3 total = "<<total<<endl;

               

                // Problem 4

                char filename[]="outdata.txt";

                char username[51];

                int age;

                cout<<"Enter user name: ";

                cin.getline(username,50,'\n');

                cout<<"Enter age: ";

                cin>>age;

               

                ofstream outfile(filename);

                if(outfile.is_open()){

                                outfile<<username<<", "<<age<<endl;

                                outfile.close();

                                cout<<"File updated successully\n";

                }else{

                                cout<<"Unable to write data to file "<<filename<<endl;

                }

}

===================================================================