Question

I need to make this program which supposed to accept the date form the user in format of YYYY-MM-DD and output the corresponding date in its expanded format.
output should be something like: Enter the date in YYYY-MM-DD: 2020-10-03
October o3, 2020

(in C++)

I have this program but there are some errors that I couldn't find.

// Lab3_Project_jk.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include<iostream>
#include<string>
using namespace std;
int main()
{
   const unsigned int VALID_DASH_INDEX_1 = 4;
   const unsigned int VALID_DASH_INDEX_2 = 6;
   const unsigned int VALID_DATE_LENGTH = 10;
   const unsigned int MIN_VALID_DAY_NUM = 1;
   string inputDate, inputYear, inputMonth, inputDay, monthName;
   unsigned int dashIndex1, dashIndex2, invalidCharIndex, inputDateLength;
   unsigned int yearNum, dayNum{}, monthNum, maxValidDayNum = 31;
   bool inputDateValid = true;

   // Get a date from the user
   cout << "Enter date in YYYY-MM-DD format: ";
   getline(cin, inputDate);

   // Check whether the input date has the correct format
   dashIndex1 = inputDate.find("-");
   dashIndex2 = inputDate.find("-", dashIndex1 + 1);
   invalidCharIndex = inputDate.find_first_not_of("0123456789-");
   inputDateLength = inputDate.size();
   if ((dashIndex1 == VALID_DASH_INDEX_1) &&
       (dashIndex2 == VALID_DASH_INDEX_2) &&
       (invalidCharIndex == string::npos) &&
       (inputDateLength == VALID_DATE_LENGTH))
   {
       // Extract the year, month and day from the input date
       inputYear = inputDate.substr(0, dashIndex1);
       inputMonth = inputDate.substr(dashIndex1 + 1, dashIndex2 - dashIndex1 - 1);
       inputDay = inputDate.substr(dashIndex2, inputDateLength - dashIndex2 - 1);

       // Convert the year, month and day to integers
       yearNum = stoi(inputYear);
       monthNum = stoi(inputMonth);
       dayNum = stoi(inputDay);

       // Determine the month name
       switch (monthNum) {
       case1:
           monthName = "January";
           maxValidDayNum = 31;
           break;
       case2:
           monthName = "February";
           maxValidDayNum = 29;
           break;
       case3:
           monthName = "March";
           maxValidDayNum = 31;
           break;
       case4:
           monthName = "April";
           maxValidDayNum = 30;
           break;
       case5:
           monthName = "May";
           maxValidDayNum = 31;
           break;
       case6:
           monthName = "June";
           maxValidDayNum = 30;
           break;
       case7:
           monthName = "July";
           maxValidDayNum = 31;
           break;
       case8:
           monthName = "August";
           maxValidDayNum = 31;
       case9:
           monthName = "September";
           maxValidDayNum = 30;
           break;
       case10:
           monthName = "October";
           maxValidDayNum = 31;
           break;
       case11:
           monthName = "November";
           maxValidDayNum = 30;
           break;
       case12:
           monthName = "December";
           maxValidDayNum = 31;
           break;
       default:
           inputDateValid = false;
       }

       // Check whether the day number is valid
       if ((dayNum < MIN_VALID_DAY_NUM) && (dayNum > maxValidDayNum)) {
           inputDateValid = false;
       }
   }
   else {
       inputDateValid = true;
   }
   // Output the date in expanded format
   if (inputDateValid) {
       cout << monthName << " " << dayNum << ", " << inputYear << " "<< endl;
   }
   else {
       cout << "Invalid date format" << endl;
   }
   return 0;
}

Answer 1

#include<iostream>
#include<string>

using namespace std;
int main()
{
const unsigned int VALID_DASH_INDEX_1 = 4;
const unsigned int VALID_DASH_INDEX_2 = 7;
const unsigned int VALID_DATE_LENGTH = 10;
const unsigned int MIN_VALID_DAY_NUM = 1;
string inputDate, inputYear, inputMonth, inputDay, monthName;
unsigned int dashIndex1, dashIndex2, inputDateLength;
int invalidCharIndex;
unsigned int yearNum, dayNum{}, monthNum, maxValidDayNum = 31;
bool inputDateValid = true ;

// Get a date from the user
cout << "Enter date in YYYY-MM-DD format: ";
getline(cin, inputDate);

// Check whether the input date has the correct format
dashIndex1 = inputDate.find("-");

dashIndex2 = inputDate.find("-",dashIndex1+1);
  
invalidCharIndex = inputDate.find_first_not_of("0123456789-");
  
inputDateLength = inputDate.size();

if ((dashIndex1 == VALID_DASH_INDEX_1) &&
(dashIndex2 == VALID_DASH_INDEX_2) &&
(invalidCharIndex == string::npos) &&
(inputDateLength == VALID_DATE_LENGTH))
{
// Extract the year, month and day from the input date
inputYear = inputDate.substr(0, dashIndex1);

inputMonth = inputDate.substr(dashIndex1 + 1, dashIndex2 - dashIndex1 - 1);

inputDay = inputDate.substr(dashIndex2+1, inputDateLength - dashIndex2 );

// Convert the year, month and day to integers
yearNum = stoi(inputYear);
monthNum = stoi(inputMonth);

dayNum = stoi(inputDay);
// Determine the month name
switch (monthNum) {
case 1:
monthName = "January";
maxValidDayNum = 31;
break;
case 2:
monthName = "February";
maxValidDayNum = 29;
break;
case 3:
monthName = "March";
maxValidDayNum = 31;
break;
case 4:
monthName = "April";
maxValidDayNum = 30;
break;
case 5:
monthName = "May";
maxValidDayNum = 31;
break;
case 6:
monthName = "June";
maxValidDayNum = 30;
break;
case 7:
monthName = "July";
maxValidDayNum = 31;
break;
case 8:
monthName = "August";
maxValidDayNum = 31;
case 9:
monthName = "September";
maxValidDayNum = 30;
break;
case 10:
monthName = "October";
maxValidDayNum = 31;
break;
case 11:
monthName = "November";
maxValidDayNum = 30;
break;
case 12:
monthName = "December";
maxValidDayNum = 31;
break;
default:
inputDateValid = false;
}

// Check whether the day number is valid
if ((dayNum < MIN_VALID_DAY_NUM) && (dayNum > maxValidDayNum)) {
inputDateValid = false;
}
}
else {
inputDateValid = true;
}
// Output the date in expanded format
  
if (inputDateValid) {
cout << monthName << " " << dayNum << ", " << inputYear << " "<< endl;
}
else {
cout << "Invalid date format" << endl;
}
return 0;
}

SCREEN SHOT :

OUTPUT:

Missed break statement at case 8 : so u got september .