#include <iostream>
using namespace std;
void calculate_bill(double& pizza_price);
int main()
{
cout << "Welcome to Domino's Pizzaria!\n";
cout << "\nEnter the price of the pizza: ";
double price;
cin >> price;
calculate_bill(price);
}
void add_tax(double& pizza_price)
{
pizza_price *= 0.085;
}
void calculate_tip(double& pizza_price)
{
pizza_price *= 0.15;
}
void calculate_bill(double& pizza_price)
{
add_tax(pizza_price);
calculate_tip(pizza_price);
double price = pizza_price * add_tax * calculate_tip;
cout << "The pizza with taxes and tip, your total comes to " << "$" << fixed << setprecision(2) << price;
}
The output should be like this:
Welcome to Domino's Pizzaria!
Enter the price of the pizza: 12.99
The pizza with taxes and tip, your total comes to $16.21
The problem is that every time I run the code it says I have an error at the "void calculate_bill". It also says that I have an error at setprecision in which I have no clue why. Any ideas on what I did wrong? I am still learning on how to call functions so could someone tell me if I called it correctly?
For using the std::setprecision you need to #include <iomanip>.
Also, you are sending the pizza price as a reference, this means you are actually changing it value on every function call. You then, recalculate it at the last statement in calculate_bill(), which is wrong. Try calling all functions but then just display the price from main().
And btw, you surely meant pizza_price *= 1.085; and pizza_price *= 1.15 didn't you? Otherwise the price will drop extremely fast for every pizza. Which we may like but definitely not your professor..
Related
trying to make my first post right so here goes.
I ran into this question and have not been able to figure it out. I keep receiving the error:
error C4700: uninitialized local variable 'miles' used
I have scavenged over all of StackOverflow and keep running into the same answer: I have to initialize my local variable, but when I do that I am creating a set value. I want to set my local variable 'miles' to an unknown value because I want the user to be able to set the value when the program runs.
Everything ran great until I tried to cast the end value 'miles'so that it would truncate.
Please correct me if I'm using incorrect terminology. Fresh-out-of-the-womb-to-programming. And thank you to everyone in advance.
Question:
Write a program that prompts the capacity, in gallons, of an automobile fuel tank and the miles per gallon the automobile can be driven. The program outputs the number of miles the automobile can be driven without refueling. Numbers entered for capacity must allow entry of capacity being an integer and the miles per gallon in decimals. The number of miles must be output to the next lowest integer (without decimals).
#include "stdafx.h"
//include statement
#include<iostream>
//include namespace statement
using namespace std;
//main function
int main()
{
//variable declaration
double capacity_Gallons;
double miles_Gallon;
double miles = static_cast<int>(miles < 0 ? miles - 0.5 : miles + 0.5);
//inputting capacity of automobile
cout << "Enter the capacity of the automobile fuel in gallons: ";
cin >> capacity_Gallons;
cout << endl;
//inputting the miles per Gallons
cout << "Enter the miles per gallons the automobile can be driven: ";
cin >> miles_Gallon;
cout << endl;
//calculating miles
miles = capacity_Gallons * miles_Gallon;
//display output data
cout << "Number of miles driven wihtout refueling: " << miles << endl;
//pause system for some time for user continuation
system("pause");
} //end main
You should take out that line entirely, and change the later line to double miles = capacity_Gallons * miles_Gallon;.
Instead of your handcrafted rounding code it would be better to use the standard rounding function in the display statement, ... << std::lround(miles) << ... although your assignment stipulation says you should round down , not round to nearest as you are currently doing. (So you can just cast to int there).
You don't need to declare miles there, you can declare it at the point it has a value.
#include<iostream>
int main()
{
//inputting capacity of automobile
double capacity_Gallons;
std::cout << "Enter the capacity of the automobile fuel in gallons: ";
std::cin >> capacity_Gallons;
std::cout << endl;
//inputting the miles per Gallons
double miles_Gallon;
std::cout << "Enter the miles per gallons the automobile can be driven: ";
std::cin >> miles_Gallon;
std::cout << endl;
//calculating miles
double miles = capacity_Gallons * miles_Gallon;
//display output data
std::cout << "Number of miles driven wihtout refueling: " << miles << std::endl;
//pause system for some time for user continuation
system("pause");
}
As an aside, using namespace std is a bad habit.
I have coded a program in C++ for an assignment in my C++ Intro class but I have multiple errors in the program but I can't seem to figure out how to get all of the bugs out.
The program is supposed to ask the user for the name of the movie, the number of adult and child tickets sold, and calculate the gross box office profit, net box office profit and the amount paid to the distributor.
I can't seem to figure out how to initialize the variables adultTicketPrice and
childTicketPrice and I thought I declared them and am trying to figure out if they need to get initialized if I already declared them?
And how is the childTicket price out of scope?
And why am I getting the other errors and how can I fix them?
// Michael VanZant
// Flix for Fun Profit Report
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
int main()
{
// Create all double variables
double adultTicketsSold, childTicketsSold, grossBoxProfit, netBoxProfit,
amtPaidDist, adultTicketPrice, childTicketPrice
adultTicketPrice = 12;
childTicketPrice = 7;
cout << fixed << setprecision(2);
// Create the string variable
string movieName;
// Get the name of the movie and store it in the movieName string
cout << "What is the name of the movie?";
getline(cin, movieName);
cout << "\n";
// Cin.ignore to ignore the string variable type
cin.ignore();
// Get the amount of adult and child tickets sold
cout << "How many adult tickets do you want to buy?";
cin >> adultTicketsSold;
cout << "\n";
cout >> "How many child tickets did you want to buy?";
cin >> childTicketsSold;
cout << "\n";
// Calculate the amount of gross box office profit and display it
grossBoxProfit = (childTicketsSold * childTicketPrice) + (adultTicketsSold * adultTicketPrice);
cout << "Gross Box Office Profit: $" << grossBoxProfit;
cout << "\n";
// Calculate the net box profit amount and display it
netBoxProfit = grossBoxProfit * .20;
cout << "Net Box Profit Amount: $" << netBoxProfit;
cout << "\n";
// Calculate the amount paid to distributor and display it
amtPaidDist = grossBoxProfit - netBoxProfit;
cout << "Amount Paid to Distributor is: $" << amtPaidDist;
return 0;
}
When the compiler says "expected initialiser", it has nothing to do with these lines:
adultTicketPrice = 12;
childTicketPrice = 7;
which are actually assignments, not initialisations (though some old C terminology would call the first assignment an initialisation).
No, it's because it thinks you're still on this line, providing declarations and (optionally) initialisers:
double adultTicketsSold, childTicketsSold, grossBoxProfit, netBoxProfit,
amtPaidDist, adultTicketPrice, childTicketPrice
That's because you didn't put a ; at the end of it.
Also:
cout >> "How many child tickets did you want to buy?";
You meant <<.
Fixing those two little typos, the code compiles.
c++ and I'm trying to figure out why my code returns 0's from a few statements after the user inputs some float numbers. I'm not sure why. Maybe someone can help:
This is what I get after running my method and answering the questions before it:
The number of gallons of paint required is: 0 gallons
Hours of labor that is required: 0 hours
.
Also ignore the () around my # in the beginning. I will put periods between lines to make it look neater on this website.
/**
* A painting company has determined that for every 160 square feet of wall
space, one gallon of paint and 3 hours of labor are required.
* The company charges the $28.00 per hour for labor.
* Design a modular program that allows the user to enter the number of rooms
that are to be painted,
* the approximate square feet of wall space in each room (may differ from room
to room), and the price per gallon of paint.
* It should then create a report that includes a fancy company header and
displays the following information:
* The number of gallons of paint required: (Rounded up to the next full
gallon)
* The hours of labor required:
* The cost of the paint:
* The labor charges:
* Total cost of the paint job:
* Requirements:
* Input validation: The program should not accept a value less than 1 or
more than 12 for the number of rooms
* Should not accept a value less than 100 for the square
footage of a room.
* Should not accept a value less than $10.00 or more
than $25.00 for the price of a gallon of paint
*
* Lets do this...
*/
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
float priceOfGallon(float);
float numberOfGallons(float, float);
float totalWallArea(float, float, float);
float laborHours(float, float);
void fancyCompanyHeader();
int main() {
float area;
float totalArea;
float min_labor = 3;
float number_of_rooms;
float number_of_gallons;
float price_of_gallon;
totalWallArea(area, totalArea, number_of_rooms);
priceOfGallon(price_of_gallon);
numberOfGallons(number_of_gallons, totalArea);
laborHours(number_of_gallons, min_labor);
fancyCompanyHeader();
return 0;
}
// function that gets the number of gallons needed for the total area
float numberOfGallons(float number_of_gallons, float totalArea) {
number_of_gallons = (totalArea / 160.0);
std::cout << "The number of gallons of paint required is: " <<
number_of_gallons << " gallons" << std::endl;
}
float priceOfGallon(float price_of_gallon){
std::cout << "Please enter the price per gallon: " << std::endl;
cin >> price_of_gallon;
while(price_of_gallon < 10.00 || price_of_gallon > 25.00) {
std::cout << "The price should be between $10.00 and $25.00. Please try again: " << std::endl;
cin >> price_of_gallon;
}
}
float totalWallArea(float area, float totalArea, float number_of_rooms) {
std::cout << "Please enter the number of rooms that needs to be painted:" <<
std::endl;
std::cin >> number_of_rooms;
while(number_of_rooms < 1)
{
cout << "Number of rooms must be at least one. Please try again: " <<
std::endl;
cin >> number_of_rooms;
}
for(float i = 1; i <= number_of_rooms; i++)
{
cout << "Please enter the square feet of wall space needed for Room " <<
i << std::endl;
cin >> area;
while(area < 100)
{
std::cout << "The area should be 100 or greater. Please try again: "
<< std::endl;
cin >> area;
}
totalArea += area;
}
}
// I will finish this method later
float laborHours(float number_of_gallons, float min_labor) {
min_labor = number_of_gallons * 28.00;
std::cout << "Hours of labor that is required: " << min_labor << " hours "
<< std::endl;
return min_labor;
}
You need to make all of those variables you are modifying global (Declared outside of int main()). In C++, when you give a function a variable, it will just copy the contents of the variable into the function's variables: the original variable passed in remains constant. Thus, your uninitialized floats default to 0 and are not changed by any of the functions, so when they are given to the laborHours function or numberOfHours function, 0s are passed into each.
Example with much better practices than in your code (it's ok, everyone starts by writing atrocious code) :
#include <iostream>
int walls,rooms,total_walls; //It only makes sense if all of these are integers.
//These are global declarations, they can be modified by any function in the program
void input_walls() {
/* Functions are notated as so in C++:
{return type} {function_name}({input},{input},...)
It's pointless to annotate functions that don't return anything
with a declaration of a float return type (they'll just return 0 */
std::cin >> walls;
while(walls < 0) {
std::cout << "Please input a positive amount of walls per room.";
std::cin >> walls;
}
}
void input_rooms() {
std::cin >> rooms;
while(rooms < 0) {
std::cout << "Please input a positive amount of rooms";
std::cin >> rooms;
}
}
void calculate_result() {
total_walls = walls*rooms;
}
void output_result() {
std::cout << "I'll need to paint " << total_walls << " walls!" << std::endl;
}
int main() {
input_walls();
input_rooms();
calculate_result();
output_result();
}
This still isn't the best way to write this, but it's still the exact same thing you were trying to do. Now try rewriting what you were trying to do in this style!
TLDR/Quick fix: Make the variable definitions global, cut out the arguments from the functions.
So I perused some of the other articles, but I can't seem to find a reason to why this won't work. I am new to C++ so be kind please.
// User Pay.cpp : Defines the entry point for the console application.
// This program calculates the user's pay.
#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{
double hours, rate, pay;
// Get the number of hours worked.
cout << "how many hours did you work? ";
cin >> hours;
// Get the hourly pay rate.
cout << "How much do you get paid per hour? ";
cin >> rate;
//C alculates the Pay.
pay = hours * rate;
// Display the pay.
cout << "You have earned $" << pay << endl;
return 0;
}
You dont need to include #include "stdafx.h".
Also a better practice for the future is not to include the whole std library ("using namespace std"). Instead of this you can call directly std::cout, std::cin etc...
Also a system("PAUSE") call at the end of the code before "return 0" would be helpful (in your example). So the console doesn't close when the program execute and you can see your result.
Code example:
#include <iostream>
//using namespace std;
int main()
{
double hours, rate, pay;
// Get the number of hours worked.
std::cout << "how many hours did you work? ";
std::cin >> hours;
// Get the hourly pay rate.
std::cout << "How much do you get paid per hour? ";
std::cin >> rate;
//C alculates the Pay.
pay = hours * rate;
// Display the pay.
std::cout << "You have earned $" << pay << std::endl;
system("PAUSE");
return 0;
}
Try creating an empty project (uncheck precompiled headers). then copy your code but delete #include "stdafx.h".
It looks as if you had an error, and then added:
`using namespace std;`
There should be no error now.
I just starting learning C++. Here is my code:
#include <iostream>
using namespace std;
int main() {
double hours,rate,pay;
// get the number of hours worked
cout << "How many hours did you work?";
cin>> hours;
//Get the hourly pay rate
cout<<"How much did you get paid per hour?";
cin>> pay;
// calculates the pay
pay = hours * rate;
// Display the pay
cout<<"You have earned $" << pay <<endl;
return 0;
}
I have no idea why this program is outputting the wrong numbers:
How many hours did you work?19
How much did you get paid per hour?15
You have earned $4.03179e-313
Maybe I installed the IDE wrong (I am using Eclipse)?:
I think your cin >> pay line is wrong, because you follow it up with pay = hours * rate. Since rate is never assigned to, it just gets junk data in memory, so the output is undefined. Change cin >> pay to cin >> rate
firstly, initializing variables before using them is a good practice so you shoud try this :
double hours = 0, rate = 0, pay = 0;
secondly, you need to replace pay by rate in :
//Get the hourly pay rate
cout << "How much did you get paid per hour?";
cin >> rate;
Amran AbdelKader.
There are two issues with your code.
Your second cin>> call is initializing pay when it should be initializing rate instead:
cin >> rate;
Or, if you are using C++11 or later, you can use std::get_money() instead:
cin >> get_money(rate);
Your cout<< is outputting a double (a floating-point data type) using its default formatting, which may not be suitable for your needs. To display money values, you should be explicit about the formatting, eg:
cout << "You have earned $" << fixed << setprecision(2) << pay << endl;
Or, if you are using C++11 or later, you can use std::put_money() instead:
cout << "You have earned " << put_money(pay) << endl;