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How do you access an element within a string?

oceanmachine (1)
I can't figure out the last part of this assignment ("Read the user's date of birth: 2 digits for the month and 2 digits for the day..."). I'm hoping someone here can help. Here's the prompt:

"Write a program that reads the current date from the user in 10/3/2017 format and then generates a random date such as 9/30. Make sure you use correct limits for the number of days for each month when generating the date. For example, 9/30 is valid, but not 9/31. To check for the month of February, use the current year entered by the user, since the number of days in February depends on if the year is leap year or not. Months 1, 3, 5, 7, 8, 10 and 12 are 31 days, month 2 is 29 days in a leap year and 28 in a non leap year and the rest of the months are 30 days. A year is a leap year if it's divisible by 400 or if not, it's divisible by 4 but not 100. If the generated date is the same as or following or preceding one of the following dates, generate another date: 1/1, 7/4, 11/25 and 12/25. If the second generated date is again the same or next to one of those dates, let it be. Next, read the user's date of birth: 2 digits for the month and 2 digits for the day into a c-string that has room for the 4 digits entered and then print the date of birth in October 3 format."

Here's what I have so far:

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#include<iostream>
#include<conio.h>
#include<cstdlib>
#include<ctime>
#include<string>
#include<iomanip>
using namespace std;
int main()
{
        int day1, month1, year1, day2, month2, day3;
	char slash, bday[5];

	cout << "Enter today's date as month/day/year: ";
	cin >> month1 >> slash >> day1 >> slash >> year1;
	
	unsigned seed = time(0);
	srand(seed);
	month2 = 1 + rand() % 12 + 1;
	
	if (month2 == 1 || month2 == 3 || month2 == 5 || month2 == 7 || month2 == 8 || month2 == 10 || month2 == 12)
		{
		day2 = 1 + rand() % 31 + 1;
		}
	else if (month2 == 2)
			{ 
		if ((year1 % 4 == 0 && year1 % 100 != 0) || (year1 % 400 == 0))
			{
			day2 = 1 + rand() % 29 + 1;
			}
			else
			{
			day2 = 1 + rand() % 28 + 1;
			}
			}
	else 
		{
		day2 = 1 + rand() % 30 + 1;
		}

	if (month2 == 1 && day2 == 1 || month2 == 7 && day2 == 4 || month2 == 11 && day2 == 25 || month2 == 12 && day2 == 25)
		{
		month2 = 1 + rand() % 12 + 1;
		}
			cout << "\nGenerated: " << month2 << slash << day2 << endl;

		cout << "\nEnter your date of birth as mm/dd: ";
		
		cin.getline(bday, 5);
		cin.ignore();
		
		if (bday[0] == '0' && bday[1] == '1')
			cout << "\nJanuary";
		else if (bday[0] == '0' && bday[1] == '2')
			cout << "\nFebruary";
		else if (bday[0] == '0' && bday[1] == '3')
			cout << "\nMarch";
		else if (bday[0] == '0' && bday[1] == '4')
			cout << "\nApril";
		else if (bday[0] == '0' && bday[1] == '5')
			cout << "\nMay";
		else if (bday[0] == '0' && bday[1] == '6')
			cout << "\nJune";
		else if (bday[0] == '0' && bday[1] == '7')
			cout << "\nJuly";
		else if (bday[0] == '0' && bday[1] == '8')
			cout << "\nAugust";
		else if (bday[0] == '0' && bday[1] == '9')
			cout << "\nSeptember";
		else if (bday[0] == '1' && bday[1] == '0')
			cout << "\nOctober";
		else if (bday[0] == '1' && bday[1] == '1')
			cout << "\nNovember";
		else if (bday[0] == '1' && bday[1] == '2')
			cout << "\nDecember";
		else
			cout << "\nerror" << endl;

	cout << "\nPress any key to continue.";
	_getch();
	return 0;
}
Last edited on
Enoizat (1342)
Hope this can be useful:

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// How do you access an element within a std::string?
// oceanmachine
// I can't figure out the last part of this assignment 
// ("Read the user's date of birth: 2 digits for the month and 2 digits for 
// the day..."). I'm hoping someone here can help. Here's the prompt:

// "Write a program that reads the current date from the user in 10/3/2017 
// format and then generates a random date such as 9/30. Make sure you use 
// correct limits for the number of days for each month when generating 
// the date. For example, 9/30 is valid, but not 9/31. To check for 
// the month of February, use the current year entered by the user, 
// since the number of days in February depends on if the year is leap 
// year or not. Months 1, 3, 5, 7, 8, 10 and 12 are 31 days, month 2 is 29 days
// in a leap year and 28 in a non leap year and the rest of the months 
// are 30 days. A year is a leap year if it's divisible by 400 or if not, 
// it's divisible by 4 but not 100. If the generated date is the same as or 
// following or preceding one of the following dates, generate another date: 
// 1/1, 7/4, 11/25 and 12/25. If the second generated date is again the same 
// or next to one of those dates, let it be. Next, read the user's date of 
// birth: 2 digits for the month and 2 digits for the day into a c-std::string 
// that has room for the 4 digits entered and then print the date of birth 
// in October 3 format."
#include <cstdlib>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <limits>
#include <string>
#include <vector>

struct Mydate {
    int day;
    int month;
    int year;
};

bool excludeDates(int, int);

int main()
{
    // "...Write a program that reads the current date from the user in 
    // 10/3/2017 format..."
    std::cout << "\nEnter today's date as month/day/year: ";
    std::string userdt;
    std::cin >> userdt;

    std::string::size_type pos = userdt.find_first_of("/");
    std::string tmpstr = userdt.substr(0, pos);
    Mydate userdate;
    userdate.month = std::stoi(tmpstr);

    tmpstr = userdt.substr(pos+1, userdt.find("/", pos+1));
    userdate.day = std::stoi(tmpstr);

    pos = userdt.find_last_of("/") + 1;
    tmpstr = userdt.substr(pos);
    userdate.year = std::stoi(tmpstr);

    // "...and then generates a random date such as 9/30..."
    srand(time(0));
    Mydate rnddate;
    rnddate.year = userdate.year;


    int firstattempt = 0;
    do
    {
        rnddate.month = rand() % 12 + 1;
        switch(rnddate.month)
        {
            case  2:
                // A year is a leap year if it's divisible by 400 or if not, 
                // it's divisible by 4 but not 100
                if(rnddate.year % 400 
                   || (rnddate.year % 4 && !rnddate.year % 100))
                {
                    // leap year
                    rnddate.day = rand() % 29 + 1;
                }
                else
                {
                    rnddate.day = rand() % 28 + 1;
                }
                break;
            case  4:
            case  6:
            case  9:
            case 11:
                rnddate.day = rand() % 30 + 1;
                break;
            default:
                rnddate.day = rand() % 31 + 1;
                break;
        }
        firstattempt++;
    } while(excludeDates(rnddate.day, rnddate.month) && firstattempt<2);

    char slash = '/';
    std::cout << "\nGenerated: " << rnddate.month << slash << rnddate.day 
              << std::endl;

    // "... Next, read the user's date of birth: 2 digits for the month and 
    // 2 digits for the day into a c-string that has room for the 4 digits 
    // entered and then print the date of birth in October 3 format..."
    std::cout << "\nEnter your date of birth as mm/dd: ";

    char bday[6];
    std::cin.ignore(); // <-- this will ignore one single character!
    std::cin.getline(bday, 6);

    int month = int(bday[0]-48) * 10 + int(bday[1]-48);
    std::vector<std::string> months = {"January", "February", "March",
                                       "April", "May", "June",
                                       "July", "August", "September",
                                       "October", "November", "December"};

    std::cout << months.at(month-1) << ' ' 
              << int(bday[3]-48) * 10 + int(bday[4]-48) << '\n';
    
    std::cout << "\nPress ENTER to continue...\n";
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

    return 0;
}

bool excludeDates(int day, int month)
{
    // If the generated date is the same as or following or preceding 
    // one of the following dates, generate another date: 
    // 1/1, 7/4, 11/25 and 12/25.
    switch(day)
    {
        case  1:
        case  2:
        case 31:
            if(month == 1 || month == 12) return true;
            break; // pointless, but in case of corrections...
        case  3:
        case  4:
        case  5:
            if(month == 7) return true;
            break;
        case 24:
        case 25:
        case 26:
            if(month == 11 || month == 12) return true;
            break;
    }

    return false;
}

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