Write a program that prompts the user to enter the year and the first three letters of a month name (with the first letter in up
percase) and displays the number of days in the month.
1 answer:
Answer:
I am writing a C++ program.
#include <iostream> // for input output functions
using namespace std; // to identify objects like cout, cin
int main() { // start of main() function body
int year; // stores the year entered
string month; // holds the letters of a month
cout<<"Enter the Year: "; // prompts user to enter year
cin>>year; // reads year entered by user
cout<<"Enter first three letters of a month ";
// prompts user to enter first three letters of a month
cin>>month; //reads the three letters of month entered by the user
// formula to determine leap year
bool leapYear =((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0);
//if checks if the 3 letters of input month match with one from these months
if ( month == "Jan" || month =="Mar" || month == "May" || month == "Jul" || month == "Aug"|| month == "Oct"|| month == "Dec")
//displays no of days in input month and year are 31
cout<<"Number of days in "<<month<<" "<<year<<": 31 ";
//else- if checks if the input month matches with one from these months
else if (month =="Apr" || month=="Jun"|| month == "Sep"|| month == "Nov")
//displays no of days in input month and year are 31
cout<<"Number of days in "<<month<<" "<<year<<": 30 ";
else if (month =="Feb") //if the input month is Feb
cout<<"Number of days in "<<month<<" "<<year<<": "<<((leapYear) ? 29 : 28); // checks if the year is leap if yes then displays 29 days else 28
else //if none of the above if else conditions is true
{cout<<"Not a valid entry"; //displays invalid entry
exit(0); //exits the program } }
Explanation:
The basic working of this program is briefly described in the comments above. I will explain the logic of the program.
This program takes int type year and a string month from the user (first three letters of the month).
Then it computes that if the year entered by the user is a leap year by this formula:
((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)
A leap year has 366 days and year which is not a leap year has 365 days. modulus operator is used here which returns the remainder of the division. If the input year is completely divisible by 4 which means we get remainder 0 then mod of year is taken with 100. If the input year is evenly divisible by 100 then mode of year is taken with 400. Then if the input year is completely divisible by 400 this means the year is a leap year. Otherwise, year is not a leap year.
Next the IF statement is used to check the condition if the first three letters the month entered by the user matches one of the those mentioned in the if statement. As we know that the months Jan, March, May, July, Aug, Oct and Dec have 31 days so if the input month is any of these months then the message is displayed that the month has 31 days.
If the input month is not from the above months then else-if part is checked for input month. If the input month's letters matches with any of the months in else-if condition then the message displayed that the input year and month has 30 days.
If the above if and else if statement evaluate to false then the second else-if part is executed which checks if the input month is Feb, if its true the conditional statement checks if the input year is a leap year or not. If the input year is a leap year then the month Feb has 29 days otherwise 28 days.
If none of the above conditions are true this means that the user might be entering wrong letters such as Fab or Aig etc instead of Feb or Aug, so the message printed : Not a valid entry and program exits.
Screenshot of program along with its output is attached.
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Program Explanation:
- Defining a method "dice_eval" that takes two variables "d1,d2" in its parametes.
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- In the elif block, it adds the parameters and uses or gate that check its value that is equal to 2 or 3 or 12. so, it will return a string message that is ' C r aps ! '.
- In the else block, it uses a return keyword that adds parameter value and prints a string value.
- Outside the method "d1,d2" is declared that inputs the value from the user-end, and passes the value into the method, and prints its value.
Program:
def dice_eval(d1, d2):#defining a method dice_eval that takes two parameters
if (d1+d2)==7 or (d1+d2)==11:#defining if block that adds parameter value and use or operator to check its value
return 'Winner!'#return string value
elif (d1+d2)==2 or (d1+d2)==3 or (d1+d2)==12:#defining elif block that adds parameter value and use or operator to check its value
return 'C r aps!'#return string value
else:#defining else block
return 'Point is '+str(d1+d2)#return string value with adding parameter
d1=int(input())#defining d1 that input value
d2=int(input())#defining d2 that input value
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Output:
Please find the attached file
Please find the complete code in the attached file.
Learn more:
Answer:
Here is the JAVA program that prompts the user to enter positive integers from standard input and prints out the maximum and minimum values:
import java.util.*;
public class Ex0603 {
public static void main(String[] args) { //start of main function
Scanner in = new Scanner(System.in); //creates Scanner class object to take input from user
int minimum = 0; //stores the minimum of the integers
int maximum = 0; //stores the minimum of the integers
int num; //stores the positive integer values
System.out.println("enter a positive integer: ");//prompts user to enter a positive integer
num = in.nextInt();//scans and reads the input integer value from user
minimum = num; //assigns value of num to minimum
while(true) {//while loop keeps prompting user to enter a positive integer
System.out.println("enter a positive integer: ");//prompts user to enter a positive integer
num = in.nextInt();//scans and reads the input integer value from user
if(num <=0)//if the user inputs a negative integer or 0
break; //breaks the loop
if (num > maximum) {//if the value of positive integer is greater than the maximum of value
maximum = num; } //assigns that maximum value of num to maximum variable
if (num < minimum) {//if the value of positive integer is less than the minimum of value
minimum = num; //assigns that minimum value of num to minimum } }
System.out.println("The maximum integer is : " + maximum); //displays the maximum of the positive integers
System.out.println("The minimum integer is : " + minimum); }} //displays the minimum of the positive integers
Explanation:
Here is the JAVA program that that prompts the user to enter an integer N, then reads N double values, and prints their mean (average value) and sample standard deviation:
import java.util.*;
public class Ex0603 {
public static void main(String[] args) { //start of main function
Scanner in = new Scanner(System.in); //creates Scanner class object to take input from user
double integer= 0; //to store the number of input values
double sum = 0; //to store the sum of input numbers
double mean = 0; //to store the average of numbers
double sd = 0; //to store the standard deviation result
double variance = 0; //to store the variance result
double sumSquare = 0; //to store the sum of (num-mean)^2
int n = 0; //to store the sample size N
System.out.println("Enter an integer: "); //prompts user to enter an integer that is how many elements user wants to input
integer = in.nextInt(); //reads the value of integer from user
double size=integer; // declares a double type variable and assigns value of int type variable integer to this double type variable size
int i=0; //used to point each element of the num array
double num[] = new double[(int)size]; //declares an array to hold the numbers input by user
while(integer>0){ //loop executes until value of integer is greater than 0
System.out.println("Enter a number: "); // prompts to enter a number
num[i] = in.nextDouble(); //reads double values
sum += num[i]; //adds the values stored in num array
i++; //increments i to point to the next element in num array
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integer--; //decrements integer value at each iteration
mean = sum / n; } //compute the average of values
i=0;
while(size>0){ //loop executes until value of size exceeds 0
sumSquare += Math.pow(num[i]-mean,2); //takes the sum of square difference between each element of num array and value of mean
i++; //increments i
size--; } //decrements size
variance = sumSquare / (n-1); //compute variance by dividing the result of sum of the squares of their differences from the mean by n-1
sd = Math.sqrt(variance); //computes standard deviation by using sqrt function which takes the sqrt of the result of variance computed above
System.out.println("Average value is: " + mean+ " and the standard deviation is " + String. format("%.2f", sd)); }} //displays the average of numbers stored in mean variable and value of standard deviation is displayed up to 2 decimal places
Screenshots of both programs and their outputs is attached.
