Suppose that the tuition for a university is $10,000 this year and increases 5% every year. In one year, the tuition will be $10,500. Write a program that computes the tuition in ten years and the total cost of four years' worth of tuition after the tenth year.
I can calculate the tenth year tuition easily enough. What has me stumped is how to add the unique tuition values at years 11, 12, 13 and 14.
double Fee = 10000;
double Year = 1;
double TotalFee;
double Rate = 5;
double TotalCost = 15000 + 15500 + 16000 + 16500;
System.out.println("Year " + " Total Fee ");
System.out.println();
while (Year <= 14) {
TotalFee = Fee + ((Fee * ((Year * Rate) - Rate)) / 100);
System.out.println(Year + " " + " "+ TotalFee);`
Year++;
}
System.out.println("Total cost tuition of 4 years starting 10 years from now is " + TotalCost);
The last while loop is my attempt at adding the 4 years. How could I pull out the unique values of TotalCost at iterations 11 to 14 and add them?
Since you want to increase the amount 5% every year, instead of having rate = 5
You should have rate = 1.05.
With the rate as 1.05 you can do this
FeeAtYear1 = 10000*1.05^0 = 10000
FeeAtYear2 = 10000*1.05^1 = 10500
FeeAtYear3 = 10000*1.05^2 = 11025
FeeAtYear4 = 10000*1.05^3 = 11576.25
...
FeeAtYear10 = 10000*1.05^9 = ~16288.95
You don't even need a while loop.
TotalCost = 10000 *1.05^10 + 10000 *1.05^11 + 10000 *1.05^12 + 10000 *1.05^13;
Related
I have to do an assignment for my class that allows the user to key in two amounts - the first should be the total sale amount and the next would be the amount of change handed to the cashier. The program needs to calculate the change needed and tell the cashier how many of each monetary amount to return to the customer using the least number of bills and coins. Using $20, 10, 5, 1 and 0.25, 0.10, 0.05, and 0.01. I also need to include a while loop to make sure the cashier is given an amount greater than the amount due.
I have the following so far, but don't know where to go from here:
public class Change {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
//Enter sale amount less than $100
System.out.println("Enter the sale amount: ");
double price = input.nextDouble();
//Enter amount of money handed to cashier less than $100
System.out.println("Enter the amount of money handed to the cashier: ");
double payment = input.nextDouble();
double difference = payment - price;
int num20 = (int)(difference / 20);
System.out.println("num20 = " + num20);
difference = difference % 20;
System.out.println("difference = " + difference);
int num10 = (int)(difference / 10);
System.out.println("num20 = " + num10);
difference = difference % 10;
System.out.println("difference = " + difference);
int numQtr = (int)(difference / .25);
System.out.println("numqtr = " + numQtr);
int numDime = (int)(difference / .10);
System.out.println("numDime = " + numDime);
}
Use the mod operator and division to find values at each step
29 % 20 -> 9
(int) (29 / 20) -> 1
9 % 10 -> 9
(int) (9 / 10) -> 0
please note that casting the result of a division to an integer will truncate the returned value to a whole number.
I'm making a program that calculates the population for a year given the start year (2011) and increases the population by 1.2% every year. The population for 2011 is 7.000 (I'm using decimals, instead of billions). Here is the working part of my code
package src;
import java.util.Scanner;
import java.text.DecimalFormat;
public class Demographics {
public static void main(String[] args) {
Scanner user_input= new Scanner(System.in);
//Part 1
System.out.println("===--- Part 1 ---===");
System.out.println("Population in 2011: 7.000");
System.out.print("What is the desired year? ( > 2011) ");
int startYear = 2011;
int endYear = user_input.nextInt();
while (endYear <= startYear){
System.out.println("Invalid end year.");
System.out.print("What is the desired year? ( > 2011) ");
endYear = user_input.nextInt();
break;
}
double t = 0.012;
double nbr = (endYear - startYear);
double pStart = 7.000;
double pEnd = pStart * Math.exp(nbr * t);
DecimalFormat nf = new DecimalFormat("#.000");
System.out.println("Population in " + endYear + ":(nf.format(pEnd)));
//Part 2
System.out.println("===--- Part 2 ---===");
System.out.print("What is the target population? ( > 7.000) ");
double pTarget = user_input.nextDouble();
while (pTarget <= pStart){
System.out.println("Invalid target population.");
System.out.print("What is the target population? ( > 7.000) ");
pTarget = user_input.nextDouble();
break;
}
while (pStart < pTarget){
startYear++;
pStart = pStart + (pStart * 0.012);
System.out.println("Population in " + startYear + ": " + nf.format((pStart)));
}
}
}
Part 1 of my code calculates the population of a year when the user enters it, then part 2 shows the calculations of how many years it will take when a user enters a population to get to that point.
Here is the code that doesn't work
//Part 3
System.out.println("===--- Part 3 ---===");
t = 1.2;
pStart = 7.000;
pEnd = pStart * Math.exp(nbr * t);
while (pStart < pTarget){
startYear++;
pEnd = pStart + (pStart * 0.012);
if (pEnd >= pStart * 2 ){
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + (t / 2));
}else{
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + t);
}
}
Currently when i have part 3 in my code it does an infinite loop without multiplying the population. What I'm trying to do in part 3 is pretty much the same thing in part 2, but in part 3 it will display the population growth rate (t) and divide it by 2 every time the population doubles. For example:
Population in 2019 : 7.705 ; population growth rate : 1.2%
Population in 2020 : 7.798 ; population growth rate : 1.2%
Population in 2021 : 7.892 ; population growth rate : 1.2%
...
Population in 2068 : 13.873 ; population growth rate : 1.2%
Population in 2069 : 14.040 ; population growth rate : 0.6%
Anyone have any ideas on how to achieve this?
if you have problems in the loop the reason is in the condition!
while (pStart < pTarget){
so to end this code, inside the loop one of this situation has to happen:(according with your condition)
A)pStart should increase in value
B)pTarget should decrement in value
C)a "break;" have to occur
in your code you increase: startYear and pEnd, but this are not the condition to close the loop according with your condition. (i write it before:A,B,C)
1) also startYear are not re initialize it before the loop, and start already at a high value. you have to add bedore the loop:
startYear = 2011;
2) you should as far as possible to create new variables for the segment 3, is not to have problems like the one just described, is to be clear about what you are doing.
my advice for part three is this:
(Considering that I have no clear what I wanted to do reading your code, you have to cange it and make it good for you)
System.out.println("===--- Part 3 ---===");
t = 1.2;
startYear = 2011; // I add it
double pEveryYear = 7000;
while (pEveryYear < pTarget){
startYear++;
pEveryYear = pEveryYear + (pEveryYear * 0.012);
if (pEveryYear >= pTarget ){ // this condition cange only the print in the console
System.out.println("Population in " + startYear + ": " + nf.format((pEveryYear)) + " Population growth rate " + ": " + (t / 2));
break; // if you write it before the system.out you can't read it in the console.
}else{
System.out.println("Population in " + startYear + ": " + nf.format((pEveryYear)) + " Population growth rate " + ": " + t);
}
}
}
this the console output for input like "8000":
===--- Part 3 ---===
Population in 2012: 7084.000 Population growth rate : 1.2
Population in 2013: 7169.008 Population growth rate : 1.2
Population in 2014: 7255.036 Population growth rate : 1.2
Population in 2015: 7342.097 Population growth rate : 1.2
Population in 2016: 7430.202 Population growth rate : 1.2
Population in 2017: 7519.364 Population growth rate : 1.2
Population in 2018: 7609.596 Population growth rate : 1.2
Population in 2019: 7700.912 Population growth rate : 1.2
Population in 2020: 7793.323 Population growth rate : 1.2
Population in 2021: 7886.842 Population growth rate : 1.2
Population in 2022: 7981.485 Population growth rate : 1.2
Population in 2023: 8077.262 Population growth rate : 0.6
It seems you have two variables in the while loop that you try to compare however these do not actually get updated while iterating in the while loop. So after every iteration within the loop, the while condition just stays true.
See the last few lines below for a minor change to your part 3 code :
System.out.println("===--- Part 3 ---===");
t = 1.2;
pStart = 7.000;
pEnd = pStart * Math.exp(nbr * t);
while (pStart < pTarget){
startYear++;
pEnd = pStart + (pStart * 0.012);
if (pEnd >= pStart * 2 ){
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + (t / 2));
} else {
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + t);
}
pStart = startYear; // <-- NEW, you can probably use pStart instead of startYear in this code
}
The only missing thing I see in your code is that you are not updating pStart every time you go through the loop. This will not only make your loop infinite but it's also doing a wrong calculation every time except the first iteration. I added only one line from your code:
System.out.println("===--- Part 3 ---===");
t = 1.2;
pStart = 7.000;
pEnd = pStart * Math.exp(nbr * t);
while (pStart < pTarget){
startYear++;
pEnd = pStart + (pStart * 0.012);
if (pEnd >= pStart * 2 ){
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + (t / 2));
}else{
System.out.println("Population in " + startYear + ": " + nf.format((pEnd)) + " Population growth rate " + ": " + t);
}
pStart = pEnd;
}
I am having issues figuring out exactly what is wrong with this little Electricity/Energy calculator used to calculate computer energy costs.
I'd appreciate any help.
Program:
import java.util.Scanner;
public class ElectricityCalculations {
public static void main (String [] args) {
Scanner scnr = new Scanner(System.in);
double usageHoursPerDay = 0; // Hours computer is on per day
double usageDaysPerWeek = 0; // Days computer is used per week
double usageWeeksPerYear = 0; // Weeks computer is used per year
double wattsPerHour = 0; // Watts used by computer per hour
final double COST_PER_KWH = 0.145; // Prices of power per kilowatt hour
final double LBS_CO2_PER_KWH = 0.58815; // Pounds of CO2 generated per KWH
double usageHoursPerYear = 0; // Amount of hours on per year
double usageWattHoursPerYear = 0; // Amount of watt hours consumed per year
double usageKWHPerYear = 0; // Amount of KWH used in a year
double costPerYear = 0; // Total cost per year
double lbsCO2PerYear = 0; // Total amount of CO2 in pounds released per year
// Input Values
System.out.println("How many hours is your computer on per day?");
usageHoursPerDay = scnr.nextDouble();
System.out.println("How many days per week is your computer used?");
usageDaysPerWeek = scnr.nextDouble();
System.out.println("How many weeks per year is your computer used?");
usageWeeksPerYear = scnr.nextDouble();
System.out.println("How many watts per hour does your computer use? (Suggestive value for desktop: 100, laptop: 30).");
wattsPerHour = scnr.nextDouble();
// Calculations
usageHoursPerYear = usageHoursPerDay * 365;
usageWattHoursPerYear = wattsPerHour * 8760; // 8760 is the number of hours in a year
usageKWHPerYear = usageWattHoursPerYear / 1000;
costPerYear = usageKWHPerYear * COST_PER_KWH;
lbsCO2PerYear = LBS_CO2_PER_KWH * usageKWHPerYear;
// Printing Energy Audits
System.out.println("Computer Energy Audit");
System.out.println("You use your computer for " + usageHoursPerYear + " hours per year.");
System.out.println("It will use " + usageWattHoursPerYear + " KWH/year.");
System.out.println("Whih will cost " + costPerYear + "$/year for electricity.");
System.out.println("Generating that electricity will produce " + lbsCO2PerYear + " lbs of CO2 pollution.");
return;
}
}
Inputs:
8 hours/day
5 days/week
50 weeks/year
100 watts/hour
My (wrong output):
Computer Energy Audit:
You use your computer for 2920.0 hours per year.
It will use 876000.0 KWH/year.
Whih will cost 127.02$/year for electricity.
Generating that electricity will produce 515.2194 lbs of CO2 pollution.
Correct Output:
Computer Energy Audit:
You use your computer for 2000.0 hours per year.
It will use 200.0 KWH/year.
Which will cost 28.999999999999996 $/year for electricity.
Generating that electricity will produce 117.63 lbs of CO2 pollution.
You take in the number of days per week and weeks per year as input, but forget to use them in your calculations. Also, instead of printing KWH, you are displaying the variable storing Watt Hours.
// Calculations
usageHoursPerYear = usageHoursPerDay * usageDaysPerWeek * usageWeeksPerYear; //calculate based on time used, not 365 days in the year
usageWattHoursPerYear = wattsPerHour * usageHoursPerYear; //use variable from above line
usageKWHPerYear = usageWattHoursPerYear / 1000;
costPerYear = usageKWHPerYear * COST_PER_KWH;
lbsCO2PerYear = LBS_CO2_PER_KWH * usageKWHPerYear;
// Printing Energy Audits
System.out.println("Computer Energy Audit");
System.out.println("You use your computer for " + usageHoursPerYear + " hours per year.");
System.out.println("It will use " + usageKWHPerYear + " KWH/year."); //changed to correct variable
System.out.println("Whih will cost " + costPerYear + "$/year for electricity.");
System.out.println("Generating that electricity will produce " + lbsCO2PerYear + " lbs of CO2 pollution.");
I am trying to develop a program that calculates the sea level all the way up to the year 2100. Based on research I have found that the sea level will be 2.5 feet(which is 30 inches) - 6.5 feet(which is 78 inches). My program asks the user to enter which year they want to calculate how many inches the sea level has risen but I want the information to be random numbers per year between .3488 and .9069 inches because those are the averages per year that will make the sea level 2.5 feet and 6.5 feet. So my question is how can i generate random numbers for each year the user inputs so I can calculate how much the sea level has risen and then output that in the number of gallons.
/takes the input from the user of all the way up to which year
/they want to know the number of inches/ gallons the sea level has risen
/using reiman summs and a chart
/
/
/*******************************************************************************/
import java.util.Random;
import java.util.Scanner;
public class CalcProject
{
public static void main(String[] args)
{
//variables for the program
int year;
int numOfYears;
double leastRise = .3488; //y = .3488x , x is the inches of rainfall
double highRise = .9069; //y= .9069x , x is the inches of rainfall
double seaLevel1;
double seaLevel2;
//Describing what the program does to the user
System.out.println("This program caluclates the number of gallons / inches" +
"the sea level will rise based on your input." + "\n");
//Asking for the users year they want to calculate
System.out.println("Please enter which year you wish to know how much the water level will have risen since 2014");
Scanner scan = new Scanner(System.in);
year = scan.nextInt();
if(year <= 2014 || year > 2100)
{
do
{
System.out.println("Please enter a valid year between 2015 and 2100");
year = scan.nextInt();
} while((year <= 2014 || year > 2100));
}
//puts the year into a number of years from 2014
numOfYears = year-2014;
System.out.println("The number of years between now and the year you chose is: " + numOfYears);
//uses the least inches of sealevel
seaLevel1 = numOfYears * leastRise;
System.out.println("The total sealevel in inches is " + seaLevel1 + " for " + year);
//uses the most inches of seaLevel
seaLevel2 = numOfYears * highRise;
System.out.println("The total sealevel in inches is " + seaLevel2 + " for " + year);
//calculating radnom numbers for each year
Here is a simple way of handling the weird random numbers.
int numOfYears;
double leastRise = .3488;
double highRise = .9069;
double seaLevel3 = 0;
int i = 0;
while (i < numOfYears) {
double rand = Math.random();
if (rand >= leastRise && rand <= highRise) {
// rand is some sea level value representing a year
seaLevel3 += rand;
i++;
}
}
System.out.println("The total sealevel in inches is " + seaLevel3 + " for " + year);
I have to make this GUI that is a CD calculator.
I put in the Initial investment ($): e.g. 2000
the Annual interest rate (%): e.g. (8%)
Ending value ($): e.g. 5000
The program then outputs on a jLabel: The amount of years required are "12" (e.g.)
I need to make a do while loop and a counter.
I did the get text from the 3 text fields then add the initialInvestment with the annual rate % but having trouble with the loop and the counter?
int initialInvestment, endValue, cdvalue;
double cdValue, annualDecimalConvert, annualRate;
initialInvestment = Integer.parseInt(initialInvestmentInput.getText());
annualRate = Double.parseDouble(interestRateInput.getText())/100;
endValue = Integer.parseInt(endingValueInput.getText());
cdValue = initialInvestment + (initialInvestment * annualRate);
double a = cdValue;
while (a <= endValue){
a = a++;
yearsOutput.setText("The required year needed is: " + a);
}
You're simply adding 1 to a every iteration of the loop. So it'll take a few thousand iterations that way to fullfil the loop requirements.
What you have to do is keep adding the interest every year while keeping count of the years and only update the output after you're done looping.
int initialInvestment, endValue;
double cdValue, annualDecimalConvert, annualRate;
initialInvestment = Integer.parseInt(initialInvestmentInput.getText());
annualRate = Double.parseDouble(interestRateInput.getText())/100;
endValue = Integer.parseInt(endingValueInput.getText());
// First year interest is counted here.
cdValue = initialInvestment + (initialInvestment * annualRate);
int years = 1;
while (cdValue < endValue){
cdValue = cdValue + (cdValue * annualRate);
years++;
}
yearsOutput.setText("The required year needed is: " + years);