assignment at school asks me to find the present value using double, and void. i was able to write my code up to a certain degree but the result is not what i was expecting.. i ended up separating the present value into different section so at the end i'd multiply the amount given with the rest.. any tips on how to make the code actually work the way its supposed to?
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double payment,year_term, interest;
double sum;
double Power;
double presentv;
double present;
cout << "Hello, how are you doing?" << endl;
cout << "Please insert a payment amount" << endl;
cin >> payment;
cout << " amount inserted: " << payment << endl;
cout << "Enter number of years" << endl;
cin >> year_term;
cout << " number of years: " << year_term << endl;
cout << "Enter interest rate" << endl;
cin >> interest;
cout << " the interest is: " << interest << "%" << endl;
Presentv = ((1 - (pow((1 + interest),year_term))))/interest;
cout << " the value: " << Presentv << endl;
presentva = payment * Presentv;
cout << " the present value is: " << presentva << endl;
}
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I seem to be having a problem with a C++ coding question. It involves mathematical arithmetic and I seem to be getting all of my outputs correct except the final one. In addition to this, the decimal point format of my answers seem to be incorrect. The answers should contain two decimal places but only two out of my four decimal point answers seem to have two decimal places. When I try to use the precision() function, the answers go into scientific notation which I do not want.
Here is the question and answer:
Here is my code:
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
float principal;
float interest_rate;
float times_compounded;
cout << "Hello, please enter a value for your principal: ";
cin >> principal;
cout << principal << endl;
cout << "Please enter a value for your interest rate: ";
cin >> interest_rate;
cout << interest_rate << "%" << endl;
cout << "Please enter the number of times the interest is compounded during the year: ";
cin >> times_compounded;
cout << times_compounded << endl << endl;
float interest = interest_rate * 10.197647;
float amount = principal * pow((1 + (interest_rate/times_compounded)), times_compounded);
cout << "Interest Rate: " << setw(19) << interest_rate << "%" << endl;
cout << "Times Compounded: " << setw(17) << times_compounded << endl;
cout << "Principal: " << setw(17) << "$ " << setw(7) << principal << endl;
cout << "Interest: " << setw(20) << "$ " << interest << endl;
cout << "Amount in Savings: " << setw(9) << "$ " << amount;
return 0;
}
Here are my three inputs:
1000, 4.25, 12
Any feedback would be appreciated, thank you for your time.
First, the last value is wrong because you're using the interest rate as a normal number in the formula although it's actually a percentage. So you'd need to divide it by 100:
float amount = principal * pow((1 + ((interest_rate / 100) /times_compounded)), times_compounded);
Now for the precision, you can use std::fixed in conjunction with std::setprecision to set the default floating point printing precision when using std::cout. We can use a macro to make it more readable, like:
#define FIXED_FLOAT(x, p) std::fixed<<std::setprecision(p)<<(x)
So, the full output section would look like:
cout << "Interest Rate: " << setw(19) << FIXED_FLOAT(interest_rate, 2) << "%" << endl;
cout << "Times Compounded: " << setw(17) << FIXED_FLOAT(times_compounded, 0) << endl;
cout << "Principal: " << setw(17) << "$ " << setw(7) << FIXED_FLOAT(principal, 2) << endl;
cout << "Interest: " << setw(20) << "$ " << FIXED_FLOAT(interest, 2) << endl;
cout << "Amount in Savings: " << setw(9) << "$ " << FIXED_FLOAT(amount, 2);
Also, that interest = interest_rate * 10.197647 seems fishy. Interest should just be the amount minus the principal.
I'm trying to complete an assignment but I'm having difficulty with the math expressions and variables in general. I'm trying to make a program that takes user info on groceries and then outputs a receipt. Here is my code.
#include <iostream>
#include <string>
using namespace std;
int main()
{
//user input
string firstItem, secondItem;
float firstPrice, secondPrice;
int firstCount, secondCount;
double salesTax = 0.08675;
double firstExt = firstPrice * firstCount;
double secondExt = secondPrice * secondCount;
double subTotal = firstExt + secondExt;
double tax = subTotal * salesTax;
double total = tax + subTotal;
//user input
cout << "What is the first item you are buying?" << endl;
getline(cin, firstItem);
cout << "What is the price of the " << firstItem << "?" << endl;
cin >> firstPrice;
cout << "How many " << firstItem << "s?" <<endl;
cin >> firstCount;
cin.ignore();
cout << "What is the second item you are buying?" << endl;
getline(cin, secondItem);
cout << "what is the price of the " << secondItem << "?" << endl;
cin >> secondPrice;
cout << "How many " << secondItem << "s?" << endl;
cin >> secondCount;
// receipt output
cout << "1st extended price: " << firstExt << endl;
cout << "2nd extended price: " << secondExt << endl;
cout << "subtotal: " << subTotal << endl;
cout << "tax: " << tax << endl;
cout << "total: " << total << endl;
return 0;
}
The program output either 0 for all or negatives.
Your calculations must go after you read in the values, not before. You're making your calculations based on uninitialized variables.
A declaration and initialisation like
double firstExt = firstPrice * firstCount;
initialises firstExt to be the product of the current values AT THAT POINT of firstPrice and firstCount.
It doesn't set up some magic so that the value of firstExt is recalculated whenever the values of firstPrice or firstCount are changed.
In your case, firstPrice and firstCount are uninitialised variables when you do this. Accessing values of uninitialised variables of type int gives undefined behaviour.
What you need to do is something like
cout << "What is the price of the " << firstItem << "?" << endl;
cin >> firstPrice;
cout << "How many " << firstItem << "s?" <<endl;
cin >> firstCount;
firstExt = firstPrice*firstCount; // do the calculation here
If the value of firstExt is not needed until this point, you can declare it here instead;
double firstExt = firstPrice*firstCount; // do the calculation here
which means any earlier use of firstExt will give a compiler diagnostic.
So I'm writing a basic application and for some reason when I run the program a bunch of numbers pop up before my intended output. It was working fine until I added the "std::cout" lines to have the outputs only be 2 decimals. The general gist of the application is a program acts as a self-checkout register at a store and lets the user buy 2 items. And yes I know the code probably looks really bad, I'm still super new to C++.
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
float price1;
float number1;
float price2;
float number2;
float priceofitemplustax1;
float priceofitemplustax2;
float total;
std::cout << std::fixed;
std::cout << std::setprecision(2);
std::cout << price1;
std::cout << price2;
std::cout << priceofitemplustax1;
std::cout << priceofitemplustax2;
std::cout << total;
cout << endl << "Please scan your first item." <<endl;
cin.get();
cout << endl << "How many of that item are you buying? "<<endl;
cin >> number1;
cout << endl << "How much is that item?"<<endl;
cin >> price1;
priceofitemplustax1 = (number1 * price1) * 1.0875;
cout << endl << "So you want " << number1 << " of this item? Adding tax that will be " << priceofitemplustax1 << "."<<endl;
cin.get();
cout << endl << "Please scan your second item."<<endl;
cin.get();
cout << endl << "How many of that item are you buying? "<<endl;
cin >> number2;
cout << endl << "How much is that item?"<<endl;
cin >> price2;
priceofitemplustax2 = (number2 * price2) * 1.0875;
cout << endl << "So you want " << number2 << " of this item? Adding tax that will be " << priceofitemplustax2 << "."<<endl;
cin.get();
total = priceofitemplustax1 + priceofitemplustax2;
cout << endl << "So your final total for this shopping trip including tax is " << total << "."<<endl;
cin.get();
cout << endl << "Your reciept will print below."<<endl;
cin.get();
cout << setw(14) << right << "Number of Item" << setw(10) << right << "Price" << setw(20) << "Price plus tax" << endl;
cout << setw(14) << right << number1 << setw(10) << right << price1 << setw(20) << priceofitemplustax1 << endl;
cout << setw(14) << right << number2 << setw(10) << right << price2 << setw(20) << priceofitemplustax2 << endl;
cout << endl;
cout << endl;
cout << setw(8) << right << "Total is" << setw(10) << total << price2 << endl;
cin.get();
}
std::cout << std::setprecision(2);
std::cout << price1;
std::cout << price2;
std::cout << priceofitemplustax1;
std::cout << priceofitemplustax2; std::cout << total;
here you write 5 floats
The lines
std::cout << std::fixed; // sets a format
std::cout << std::setprecision(2); // sets a format
set the streams output format.
The lines
std::cout << price1; // outputs a number
std::cout << price2; // outputs a number
std::cout << priceofitemplustax1; // outputs a number
std::cout << priceofitemplustax2; // outputs a number
std::cout << total; // outputs a number
print the variables to the stream.
Just remove the variable output lines. Do not accept this answer - Credit goes to manni66
I'm having some issues using setprecision. I don't understand how it works completely. I searched the problem and was able to extrapolate some code that should've worked. I don't understand why it's not. Thank you for your help, I'm still kind of new at this.
//monthly paycheck.cpp
//Paycheck Calculator
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
int main() {
//Constants
const double
FEDERAL_TAX = 0.15, //Federal Tax
STATE_TAX = 0.035, //State Tax
SSA_TAX = 0.085, //Social Security & Medicare
HEALTH_INSURANCE = 75; //Health Insurance
//Variables
int year;
double grossAmount;
string employeeName, month;
// Initialize variables with input
cout << "Hello, what's your first name? ";
cin >> employeeName;
cout << "What is your gross amount? ";
cin >> grossAmount;
cout << "Please enter the month and year: ";
cin >> month >> year;
// Output
cout << "***********************************" << endl;
cout << "Paycheck" << endl;
cout << "Month: " << month << "\tYear: " << year << endl;
cout << "Employee Name: " << employeeName << endl;
cout << "***********************************" << endl;
cout << setprecision(5) << fixed;
cout << "Gross Amount: $" << grossAmount << endl;
cout << "Federal Tax: $" << FEDERAL_TAX*grossAmount << endl;
cout << "State Tax: $" << STATE_TAX*grossAmount << endl;
cout << "Social Sec / Medicare: $" << SSA_TAX*grossAmount << endl;
cout << "Health Insurance: $" << HEALTH_INSURANCE << endl << endl;
cout << "Net Amount: $" << fixed << grossAmount-grossAmount*(FEDERAL_TAX+STATE_TAX+SSA_TAX)-HEALTH_INSURANCE << endl << endl;
system("PAUSE");
return 0;
}
If you want to format floats to display with 2 decimal places in C++ streams, you could easily:
float a = 5.1258f;
std::cout << std::fixed << std::setprecision(2) << a << std::endl;
See std::fixed and std::setprecision
Use stream manipulators:
std::cout.fixed;
std::cout.precision(Number_of_digits_after_the_decimal_point);
I am having a couple problems with my code.
First off, with the code like it is, No matter what information I put in, It always returns 0, Any suggestions on where to fix this and how? I believe it has something to do with my Class Employee. How would I go about fixing this?
Second, How do I access the information in int total()? I need to access it for the last bit of code.
Also if you notice anything else that I can do to optimize my program, I welcome your suggestions. I am learning C++ as I go and will always be a Student.
// Datamax.cpp
// Created by Kennith Adkins
#include <iostream>
#include <string>
using namespace std;
class Employee
{
public:
string eName;
float eHours;
float eWage;
float ePay;
float eOvertimeHours;
float eOvertimePay;
float eTotalPay;
float eTotalBaseHours;
float eTotalSalary;
float eTotalOvertimeHours;
int Overtime ()
{
if (eHours > 40)
{
eOvertimeHours = (eHours - 40);
eOvertimePay = (eOvertimeHours * (eWage * 1.5));
ePay = ((eHours - eOvertimeHours) * eWage);
eTotalPay = ePay + eOvertimePay;
}
else
{
ePay = (eHours * eWage);
}
}
int total()
{
eTotalBaseHours = (employee1.eHours - employee1.eOvertimeHours) + (employee2.eHours - employee2.eOvertimeHours) + (employee3.eHours - employee3.eOvertimeHours);
eTotalSalary = (employee1.eTotalPay + employee2.eTotalPay + employee3.eTotalPay);
eTotalOvertimeHours = (employee1.eOvertimeHours + employee2.eOvertimeHours + employee3.eOvertimeHours);
}
} employee1, employee2, employee3;
// Start the main program here
int main()
{
// Gretting
cout << "Welcome to the Employee Pay Center\n";
// Employee1 information
cout << "Enter the employee name: ";
cin >> employee1.eName;
cout << "Enter the hours worked: ";
cin >> employee1.eHours;
cout << "Enter his or her hourly wage: ";
cin >> employee1.eWage;
cout << endl; // Adding a blank line to space the information out
// Employee2 information
cout << "Enter the employee name: ";
cin >> employee2.eName;
cout << "Enter the hours worked: ";
cin >> employee2.eHours;
cout << "Enter his or her hourly wage: ";
cin >> employee2.eWage;
cout << endl; // Adding a blank line to space the information out
// Employee3 information
cout << "Enter the employee name: ";
cin >> employee3.eName;
cout << "Enter the hours worked: ";
cin >> employee3.eHours;
cout << "Enter his or her hourly wage: ";
cin >> employee3.eWage;
cout << endl; // Adding a blank line to space the information out
// Returning the information to the Employeer
cout << "Employe Name ............ = " << employee1.eName << "\n";
cout << "Base Pay................. = " << employee1.ePay << "\n";
cout << "Hours in Overtime........ = " << employee1.eOvertimeHours << "\n";
cout << "Overtime Pay Amount...... = " << employee1.eOvertimePay << "\n";
cout << "Total Pay................ = " << employee1.eTotalPay << "\n\n";
cout << "Employe Name ............ = " << employee2.eName << "\n";
cout << "Base Pay................. = " << employee2.ePay << "\n";
cout << "Hours in Overtime........ = " << employee2.eOvertimeHours << "\n";
cout << "Overtime Pay Amount...... = " << employee2.eOvertimePay << "\n";
cout << "Total Pay................ = " << employee2.eTotalPay << "\n\n";
cout << "Employe Name ............ = " << employee3.eName << "\n";
cout << "Base Pay................. = " << employee3.ePay << "\n";
cout << "Hours in Overtime........ = " << employee3.eOvertimeHours << "\n";
cout << "Overtime Pay Amount...... = " << employee3.eOvertimePay << "\n";
cout << "Total Pay................ = " << employee3.eTotalPay << "\n\n";
cout << "*******************************************************\n";
cout << "*****************EMPLOYEE SUMMARY DATA*****************\n";
cout << "*******************************************************\n";
cout << "** Total Employee Salaries............ " << "**\n";
cout << "** Total Employee Hours............... " << "**\n";
cout << "** Total Overtime Hours............... " << "**\n";
cout << "*******************************************************\n";
cout << "*******************************************************\n";
return 0;
}
Hey Guys, Thanks for the help. I have most of it done now. It is displaying all the information. I am now just working on getting it to display the Employee Summary Data. I revamped my code to make it cleaner because I was trying every suggestion given to me as I learn best by hands on.
That's what you get for using non-initialized variables. You have set no value to your class members, you can't expect the compiler to guess what is your employee's name or total pay.
You need to use the form:
object name.member name = value
Of course, you should call the functions before outputting results that are supposed to be produced by these functions:
employee1.Overtime();
employee2.Overtime();
employee3.Overtime();