Convert Month Name to Month Number

Personally I believe the best way is to keep the letters and strings away from the code. Make a table similar to this:

const char * month_names[] = {
  "jan", "feb", "mar", "apr", "may", "jun", "jul", "aug",
  "sep", "oct", "nov", "dec", NULL };

Then make a function like this:

int month_number_from_name(const char * name)
{
   int i = 0;
   while (i < 12) {
      if (strcasecmp(month_names[i],name) == 0)
         break;
      ++i;
   }
   if (i == 12) {
      // 'name' wasn't recognized as a month name.
      return 0;
   } else {
      return i + 1; // to get month number in range 1..12
   }
}

This is the "best" way to solve this problem, it is also easy to expand on it if you need more advanced features. For example you would like to be able to understand several languages, in this case several strings may map to the same month number.

Make a struct:

struct entry {
   const char * name;
   int id;
};

entry month_table[] = {
  { "jan", 1 }, { "feb", 2 }, ...  { NULL, 0 } };

int month_number_from_name(const char * name)
{
   entry * p = month_table;
   while (p -> name != 0) {
      if (strcasecmp(p -> name, name) == 0)
         return p -> id;
      ++p;
   }
   return 0;
}

If you want to allow the user to abbreviate the month name as long as it stays unique, you can instead of strcasecmp use strncasecmp and compare the number of characters the user provided. In this case you should probably make a special check for length being at least 2 chars and when finding a match you shouldn't just return it but rather save it and then if you didn't find a conflicting match you return it, if you found an exact match you return that but if you found 2 partial matches that both matched you should return error.

Either way, this is the most flexible solution to the problem.

Alf

Try this one:

#include <iostream>
#include <string>
using namespace std;

class Month {
private:
        string MonthName;
        int month;
public:
        Month(string mName) { MonthName = mName;}
        Month() { MonthName = "";}
        void getMonthName();
        void displayMonthNumber();
};

void Month::getMonthName()
{
        cout << "Enter Month Name => ";
        cin >> MonthName;
        cout << endl;

        return;
}

void Month::displayMonthNumber()
{
        if (MonthName == "Jan") month = 1;
        if (MonthName == "Feb") month = 2;
        if (MonthName == "Mar") month = 3;
        if (MonthName == "Apr") month = 4;
        if (MonthName == "May") month = 5;
        if (MonthName == "Jun") month = 6;
        if (MonthName == "Jul") month = 7;
        if (MonthName == "Aug") month = 8;
        if (MonthName == "Sep") month = 9;
        if (MonthName == "Oct") month = 10;
        if (MonthName == "Nov") month = 11;
        if (MonthName == "Dec") month = 12;

        cout << month << endl;

        return;
}

int main()
{
        Month M1;

        M1.getMonthName();

        M1.displayMonthNumber();
        return 0;
}

In this cases I like to use a map, perhaps it is less
efficient but it is by far the more elegant solution. This
way you can find by a string key the int value.

#include <map>

typedef map<string,int> MonthMap;

MonthMap maps;

int main()
{
  maps["Jan"] = 1;
  /*..Add here all the names*/
  /*You can even use multimap if you want several names
    to point to the same month.
    Don't forget to convert the string to lower cases.
  */
  return 0;
}