For some reason the average is being populated wrong when I pass the array to the method I get a really low percent. It almost seems like since the Array shotsMade is only recording integers for made shots and not misses it is not calculating off the right base.
import java.util.*;
public class Test {
public static void main(String[] args) {
int myGameCounter = 1;
int shotCount = 0;
int shotCount1 = 0;
int [] shotsMade = new int [5];
int sum = 0;
System.out.print("Enter Player's Free Throw Percentage: ");
Scanner input = new Scanner(System.in);
int percent = input.nextInt();
//Game #1
System.out.println("Game " + myGameCounter + ":");
Random r = new Random();
myGameCounter++;
shotCount = 0;
for (int i = 0; i < 10; ++i){
boolean in = tryFreeThrow(percent);
if (in) {
shotCount++;
System.out.print("In" + " ");
}
else {
System.out.print("Out" + " ");
}
}
System.out.println("");
System.out.println("Free throws made: " + shotCount + " out of 10");
shotsMade[0]= shotCount;
//Game #2
System.out.println("");
System.out.println("Game" + myGameCounter + ":");
myGameCounter++;
shotCount1 = 0;
for (int i = 0; i < 10; ++i){
boolean in = tryFreeThrow(percent);
if (in) {
shotCount1++;
System.out.print("In" + " ");
}
else {
System.out.print("Out" + " ");
}
}
System.out.println("");
System.out.println("Free throws made: " + shotCount1 + " out of 10");
shotsMade[1]= shotCount1;
System.out.println("");
System.out.println("Summary:");
System.out.println("Best game: " + max(shotsMade));
System.out.println("Total Free Throws Made: " + sum(shotsMade) + " " + "out of 20");
System.out.println("Average Free Throw Percentage: " + average(shotsMade) +"%");
}//main
public static boolean tryFreeThrow(int percent) {
Random r = new Random();
int number = r.nextInt(100);
if (number > percent){
return false;
}
return true;
}
public static float average(int nums[]) {
int total = 0;
for (int i=0; i<nums.length; i++) {
total = total + nums[i];
}
float f = (total / nums.length);
return (float)total /(float)nums.length;
}
public static int sum(int nums[]) {
int sum = 0;
for (int i=0; i<nums.length; ++i) {
sum += nums[i];
}
return (int)sum;
}
public static int max(int nums[]) {
int max=nums[0];
for (int i=1; i<nums.length; i++) {
if (nums[i] > max)
max = nums[i];
}
return max;
}
}//class
You are calculating the avarage of 5 numbers but you only set 2. So if all shots hit your array will look like this: 10, 10, 0, 0, 0 and the avarage will be 4.
Old issue, you are using integer arithmetic total / nums.length with returns you an int value. You later assign it to a float, but the value already has been truncated.
Just change one of the values to float before the division, v.g. ((float) total) / num
Among others, your expression
float f = (total / nums.length);
will yield an inaccurate result.
Both total and nums.length are integers, and any operation between integers always results in an integer.
Example: if total=10 and nums.length=3, you'd expect the result to be 3.333... but actually the result is just 3. Only after that do you cast it to a float, resulting in 3.0.
To get the required result, you need to cast both integers to floats before dividing:
float f = (float) total / (float) nums.length;
Related
What I'm trying to do is generate a set of 20 different random numbers, then display the average, number of positive numbers and number of negative numbers. I'm stumped on generating the set of numbers to use, but I think I have everything else done right.
int positive = 0;
int negative = 0;
int count = 0;
int total = 0;
int average;
Random r = new Random();
int number = 0;
while (count > 20) {
number = r.nextInt(200);
total += number;
count++;
if (number > 0) {
positive++;
}
else if (number < 0) {
negative++;
}
}
average = (double) total / count;
System.out.println("The number of positives is " + positive + " ");
System.out.println("The number of negatives is " + negative + " ");
System.out.printf("The average is: " + average);
Here is a way for you to total up 20 random numbers from 0-100 and then display the result.
private int total = 0;
private int i = 0;
private Random generator = new Random();
private int pos = 0;
private int neg = 0;
private int max_int = Integer.MIN_VALUE;
private int min_int = Integer.MAX_VALUE;
private int x;
while(i < 20){
x = (int) int val = 100 - generator.nextInt(200);
if(x > max_int)
max_int = x;
if(x < min_int)
min_int = x;
if(x >= 0)
pos ++;
else
neg ++;
total += x
i++;
}
System.out.println(total / 20.0);
System.out.println("Positive number count :: " + pos);
System.out.println("Positive number count :: " + neg);
System.out.println("Max :: " + max_int);
System.out.println("Min :: " + min_int);
I'm trying to print the count of numbers in the array that are greater than 5.5, but I have no idea where to start. I got the following code:
package les5;
import java.util.*;
public class Les5 {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("How many numbers would you like to add? ");
int totalNumbers = s.nextInt();
double[] number = new double[totalNumbers];
for (int i = 1; i <= totalNumbers; i++) {
System.out.print("Number 1 " + i + ": ");
number[i - 1] = s.nextDouble();
}
int numbCount = number.length;
double avgNumber = Arrays.stream(number).sum() / number.length;
System.out.println("Numbers count: " + numbCount);
System.out.println("Average: " + avgNumber);
}
}
At the end it has to say: "Total numbers greater than 5.5: x"
Could anyone help me out?
Just iterate over the array and at each step check whether the current array element is greater than 5.5. If it is, increase a counter variable by 1.
double[] number = {10, 2, 3, 5, 6, 5.6};
int count = 0;
for (int i = 0; i < number.length; i++) {
if (number[i] > 5.5) {
count++;
}
}
System.out.println("Total numbers greater than 5.5: " + count);
public class Les5 {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("How many numbers would you like to add? ");
int N = s.nextInt();
double[] number = new double[N];
//
int greaterThan5 = 0;
for (int i = 0; i <= totalNumbers; i++) {
System.out.print("Number " + i + ": ");
number[i] = s.nextDouble();
if(number[i] >5.5)
greaterThan5++;
}
int numbCount = number.length;
double avgNumber = Arrays.stream(number).sum() / number.length;
System.out.println("Numbers count: " + numbCount);
System.out.println("Average: " + avgNumber);
System.out.println("Greater than 5: " + greaterThan5);
}
}
I need to calculate the sum of 2^0+2^1+2^2+...+2^n, where n is a number entered by the user. The main problem is that I don't know how to use the while loop to sum the different result of 2^n up.
Here is what I've tried:
import java.util.Scanner;
public class SumOfThePowers {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
System.out.println("Type a power: ");
int power = Integer.parseInt(reader.nextLine());
int number = 2;
int i = 0;
double sum = 0;
while(power <= i) {
Math.pow(number, i);
sum = sum + Math.pow(number, i);
i = i + 1;
}
int result = (int)Math.pow(number, i);
System.out.println("The sum is: " + result);
}
}
Only you have to do is:
import java.util.Scanner;
public class SumOfThePowers {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
System.out.println("Type a power: ");
int power = Integer.parseInt(reader.nextLine());
double sum = Math.pow(2,power+ 1 ) - 1;
System.out.println("The sum is: " + sum);
}
}
In this link explains the math expresion
All fine, just a few changes.
Change the parts code to
System.out.println("Type a power: ");
int power = Integer.parseInt(reader.nextLine());
int number = 2;
int i = 0;
double sum = 0;
/*Remove this --------> while(power <= i) {*/
while (i <= power) {//it should be this
/*Remove this -------> Math.pow(number, i);*/
sum = sum + Math.pow(number, i);
i = i + 1;
}
System.out.println("The sum is: " + sum);
Your conditional is backwards, it should read:
while (i <= power)
You compute the sum of powers, then completely ignore it, just printing out the result of 2^i. you should be printing out sum, something like:
while (i <= power) {
sum += Math.pow(number, i);
i++;
}
System.out.println("The sum is: " + sum);
For style points this won't handle a negative power, so you'll need to test for that.
Dont understand why do you want to loop in this case. You can do it like :
System.out.println("The sum is: "+(Math.pow(2, power+1)-1 ));
But if you really want to use loop try this :
Scanner reader = new Scanner(System.in);
System.out.println("Type a power: ");
int power = Integer.parseInt(reader.nextLine());
int number = 2;
int i = 0;
double sum = 0;
while(i<=power) {
sum = sum + Math.pow(number, i);
i = i + 1;
}
int result = (int)Math.pow(number, i);
System.out.println("The sum is: " + sum);
Here is a solution with comments to explain the logic. While loops need some kind of variable to control the number of iterations. That variable of course needs to be updated somewhere inside the loop.
You can compute the sum of the powers with the Math.pow() function, obviously. No import statement is needed to use it. I hope this helps. Good luck.
/* Scanner and variable to get and hold user input */
Scanner scan = new Scanner( System.in );
int userInput = 0;
/* Variable to hold the sum, initialized to 0.0 */
double sum = 0.0;
/* Prompt the user, and obtain the reply */
System.out.print( "Enter the exponent: ");
userInput = scan.nextInt();
/* The while loop and it's initialized counter */
int counter = 0;
while( counter <= userInput ){
/* Add each power to sum using Math.pow() */
sum = sum + Math.pow( 2, counter );
/* Watch the output as the loop runs */
System.out.println( "Sum: " + sum );
counter++; // Increment counter, so the loop exits properly
} // End while loop
public class SumofSquare {
public static void main(String[] args) {
// TODO Auto-generated method stub
String c = "123";
char d[] = c.toCharArray();
int a[] = new int[d.length + 1];
for (int i = 0; i < d.length; i++)
a[i] = d[i] - 48;
int r = 0;
for (int i = 0; i < c.length(); i++)
r = r + (int) Math.pow(a[i], a[i + 1]);
System.out.println(r);
}
}
import java.util.Scanner;
public class SumOfThePowers {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
System.out.println("Type a number:");
int power=Integer.parseInt(reader.nextLine());
int number=2;
int i=0;
int result=0;
while (power>=i) {
result += (int)Math.pow(number, i);
i++;
}
System.out.println("The result is "+result);
}
}
import java.util.Scanner;
public class SumOfThePowers {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
System.out.println("Type a number:");
double power=Double.parseDouble(reader.nextLine());
int number=2;
int i=0;
double sum=0;
while (power>=i) {
sum=sum+Math.pow(number, i);
i++;
}
System.out.println("The sum is "+sum);
}
I am not sure if what I am asking is right, but originally i had this run 5 times in the main. however i felt that a do/while loop could do the same thing. But now I cannot get the array shotsMade to change from shotsMade[0] to shotsMade[1] etc, and the shotCount to store to it. It will only store the last run of the while loop. What can I change to make those 2 items increment so the methods still calculate the data correctly
import java.util.*;
public class Final {
public static void main(String[] args) {
int myGameCounter = 1;
int [] shotsMade = new int [5];
System.out.print("Enter Player's Free Throw Percentage: ");
Scanner input = new Scanner(System.in);
int percent = input.nextInt();
//Game
do{
System.out.println("Game " + myGameCounter + ":");
Random r = new Random();
myGameCounter++;
int shotCount = 0;
for (int i = 0; i < 10; ++i){
boolean in = tryFreeThrow(percent);
if (in) {
shotCount++;
System.out.print("In" + " ");
}
else {
System.out.print("Out" + " ");
}
}
System.out.println("");
System.out.println("Free throws made: " + shotCount + " out of 10");
System.out.println("");
shotsMade[0]= shotCount;// I need shotsMade[0] to change each loop, shotsMade[1], shotsMade[2], shotsMade[3], shotsMade[4]
} while (myGameCounter <=5);
System.out.println("");
System.out.println("Summary:");
System.out.println("Best game free throws made: " + max(shotsMade));
System.out.println("Worst game free throws made: " + min(shotsMade));
System.out.println("Total Free Throws Made: " + sum(shotsMade) + " " + "out of 50");
System.out.println("Average Free Throw Percentage: " + average(shotsMade) +"%");
}
public static boolean tryFreeThrow(int percent) {
Random r = new Random();
int number = r.nextInt(100);
if (number > percent){
return false;
}
return true;
}
public static int average (int nums[]) {
int total = 0;
for (int i=0; i<nums.length; i++) {
total = total + nums[i];
}
int average = total*10 / nums.length;
return average;
}
public static int sum(int nums[]) {
int sum = 0;
for (int i=0; i<nums.length; ++i) {
sum += nums[i];
}
return (int)sum;
}
public static int max(int nums[]) {
int max = nums[0];
for (int i=1; i<nums.length; i++) {
if (nums[i] > max)
max = nums[i];
}
return max;
}
public static int min(int nums[]) {
int min = nums[0];
for (int i=1; i<nums.length; i++) {
if (nums[i] < min)
min = nums[i];
}
return min;
}
}
Two things:
Move myGameCounter++; just below where you set shotsMade[]
Otherwise, you are increasing the game counter to 2 before the first game finished.
It should look like:
shotsMade[myGameCounter-1]= shotCount;
myGameCounter++;
} while (myGameCounter <=5);
Set shotsMade[myGameCounter-1]= shotCount; instead of shotsMade[0]= shotCount;
Otherwise, you are overwriting the value of shotsMade[0]
This way, you are re-using a counter as index for the array. Since myGameCounter will increase by one after each game (after you changed point 1) and it starts from 1, using myGameCounter - 1 will yield the correct index for your array shotsMade.
My problem is that whenever I try to compile and run my program, it says one of my arithmetic problems closer to the end of my code is dividing by zero. Now there is another problem. Whenever the user is prompted to enter the number of rolls, you can input a number and hit enter, but it just skips to the next line and nothing happens. Nothing else in the code happens.
* NOTE *
I can't use arrays in this assignment because it is not covered until the next section.
Here is my assignment here. This is what i'm supposed to be doing. I can't figure out what is going wrong here. My math seems to be correct but something is going wrong.
In short my assignment wants me to find the probability of two 11 sided dice being "rolled" the amount of times the user inputs. For example:
If the user says the dice it to be rolled 100 times it would output it something like this
2s: (insert Probability of having the sum of the 2 dice being 2 after 100 rolls)
3s: (insert Probability of having the sum of the 2 dice being 3 after 100 rolls)
4s: (insert Probability of having the sum of the 2 dice being 4 after 100 rolls)
5s: (insert Probability of having the sum of the 2 dice being 5 after 100 rolls)
and so on.
Here is my code so far:
public static void main(String[] args)
{
//Declare and initialize variables and objects
Scanner in = new Scanner(System.in);
Random randNum = new Random();
int match = 0; //Number of times sum of dice matches the current sum
int die1 = 0; //Random generated numbers
int die2 = 0;
int diceTotal2 = 0;
int diceTotal3 = 0;
int diceTotal4 = 0;
int diceTotal5 = 0;
int diceTotal6 = 0;
int diceTotal7 = 0;
int diceTotal8 = 0;
int diceTotal9 = 0;
int diceTotal10 = 0;
int diceTotal11 = 0;
int diceTotal12 = 0;
int sumOfDice = 0;
double probability2 = 0.0;
double probability3 = 0.0;
double probability4 = 0.0;
double probability5 = 0.0;
double probability6 = 0.0;
double probability7 = 0.0;
double probability8 = 0.0;
double probability9 = 0.0;
double probability10 = 0.0;
double probability11 = 0.0;
double probability12 = 0.0;
//Input: ask user for number of rolls and number of sides on a die
System.out.println("Number of Rolls: ");
int rolls = in.nextInt();
//***************************************************************************************
//Using nested loops, cycle through the possible sums of the dice.
//Roll the dice the given number of times for each sum.
//Count how many times the sum of the dice match the current sum being looked for.
//***************************************************************************************
//Loop to increment through the possible sums of the dice
//Loop to throw dice given number of times
for( int numberOfRolls = 1; numberOfRolls < rolls; numberOfRolls++)
{
die1 = randNum.nextInt(6);
die2 = randNum.nextInt(6);
sumOfDice = die1 + die2;
for( ; ; )
{
//Check if the sum of dice is equal to the given sum
if(sumOfDice == 2)
{
diceTotal2++;
probability2 = diceTotal2 / numberOfRolls;
}
else if(sumOfDice ==3)
{
diceTotal3++;
probability3 = diceTotal3 / numberOfRolls;
}
else if(sumOfDice ==4)
{
diceTotal4++;
probability4 = diceTotal4 / numberOfRolls;
}
else if(sumOfDice ==5)
{
diceTotal5++;
probability5 = diceTotal5 / numberOfRolls;
}
else if(sumOfDice ==6)
{
diceTotal6++;
probability6 = diceTotal6 / numberOfRolls;
}
else if(sumOfDice ==7)
{
diceTotal7++;
probability7 = diceTotal7 / numberOfRolls;
}
else if(sumOfDice ==8)
{
diceTotal8++;
probability8 = diceTotal8 / numberOfRolls;
}
else if(sumOfDice ==9)
{
diceTotal9++;
probability9 = diceTotal9 / numberOfRolls;
}
else if(sumOfDice ==10)
{
diceTotal10++;
probability10 = diceTotal10 / numberOfRolls;
}
else if(sumOfDice ==11)
{
diceTotal11++;
probability11 = diceTotal11 / numberOfRolls;
}
else if(sumOfDice ==12)
{
diceTotal12++;
probability12 = diceTotal12 / numberOfRolls;
}
}
}
System.out.println("Sum of Dice" + " " + "Probability");
System.out.println("2s: \t\t" + probability2 + "%");
System.out.println("3s: \t\t" + probability3 + "%");
System.out.println("4s: \t\t" + probability4 + "%");
System.out.println("5s: \t\t" + probability5 + "%");
System.out.println("6s: \t\t" + probability6 + "%");
System.out.println("7s: \t\t" + probability7 + "%");
System.out.println("8s: \t\t" + probability8 + "%");
System.out.println("9s: \t\t" + probability9 + "%");
System.out.println("10s: \t\t" + probability10 + "%");
System.out.println("11s: \t\t" + probability11 + "%");
System.out.println("12s: \t\t" + probability12 + "%");
//After all throws, calculate percentage of throws that resulted in the given sum
} //end main
As you already have a solution, I would present you with another one:
import java.util.Random;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
int nRolls = 100, nDice = 6; // default values
Scanner in = new Scanner(System.in);
System.out.print("Number of throws: ");
nRolls = in.nextInt();
System.out.print("Number of sides on the dices: ");
nDice = in.nextInt();
int minSum = 2, maxSum = 2 * nDice;
int[] hist = new int[maxSum - minSum + 1];
Random rand = new Random();
for (int iter = 1; iter <= nRolls; iter++) {
int throw1 = 1 + rand.nextInt(nDice), throw2 = 1 + rand.nextInt(nDice);
int sum = throw1 + throw2;
hist[sum - minSum]++;
}
System.out.println("Number of rolls: " + nRolls);
System.out.println("Number of sides of the dice: " + nDice);
System.out.println("Sum of Dice Percentage");
for (int i = 0; i < hist.length; i++) {
System.out.println(String.format(" %2d %5.2f%%", i + minSum, hist[i] * 100.0 / nRolls));
// System.out.println(" " + (i+minSum) + " " + (hist[i]*100.0/nRolls);
}
in.close();
}
}
It shows you how to use arrays to solve this task. Each entry in the array holds the number of throws that came up with the corresponding sum. You always have 2*nDice - 1 possible sums (you can not reach 1 with two dices), so the size of the array is dependent on the number of sides on the dice.
Then you just iterate through all throws and add 1 to the corresponding histogram entry (note that I offset the histogram, so hist[0] corresponds to a sum of 2, hist[1] to a sum of 3, etc).
At the end, you can just calculate the percentage. (It's not a probability, it's the percentage that this sum occured in our simulation. If you make the number of rolls larger, this percentage will be an approximation of the probability.)
At the end, you just print it out. The String.format stuff is just for alignment of the values. If you are confused about it, just use
System.out.println(" " + (i+minSum) + " " + (hist[i]*100.0/nRolls);
instead.
Change numberOfRolls initiation to 1 instead of 0.
for( int numberOfRolls = 1; numberOfRolls <= rolls; numberOfRolls++) {
If numberOfRolls is 0, all your division operations results in divide by ZERO.
probability2 = diceTotal2 / numberOfRolls;