Sherlock and Date

Watson gives a date to Sherlock and asks him what is the date on the previous day. Help Sherlock. You are given date in DD MM YYYY format. DD is an integer without leading zeroes. MM is one of the "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November" and "December" (all quotes for clarity). YYYY is also an integer between 1600 and 2000 without leading zeroes. You have to print the date of the previous day in same format.

Example:

Input:  day = 23, m = "July", year = 1914
Output: 22 July 1914

Approach

C++

#include <bits/stdc++.h>
using namespace std;

bool checkYear(int year)
{
    if (year % 400 == 0)
        return true;
    if (year % 100 == 0)
        return false;
    if (year % 4 == 0)
        return true;
    return false;
}

void sherlockAndDate(int day, int year, string m)
{

    if (day == 1 && m == "January")
    {
        cout << 31 << " "
             << "December " << year - 1 << "\n";
    }
    else if (day == 1 && m == "February")
        cout << 31 << " "
             << "January " << year << "\n";
    else if (day == 1 && m == "March")
    {
        if (checkYear(year) == true)
            cout << 29 << " February " << year << "\n";
        else
            cout << 28 << " February " << year << "\n";
    }
    else if (day == 1 && m == "April")
        cout << 31 << " March " << year << "\n";
    else if (day == 1 && m == "May")
        cout << 30 << " April " << year << "\n";
    else if (day == 1 && m == "June")
        cout << 31 << " May " << year << "\n";
    else if (day == 1 && m == "July")
        cout << 30 << " June " << year << "\n";
    else if (day == 1 && m == "August")
        cout << 31 << " July " << year << "\n";
    else if (day == 1 && m == "September")
        cout << 31 << " August " << year << "\n";
    else if (day == 1 && m == "October")
        cout << 30 << " September " << year << "\n";
    else if (day == 1 && m == "November")
        cout << 31 << " October " << year << "\n";
    else if (day == 1 && m == "December")
        cout << 30 << " November " << year << "\n";
    else
        cout << day - 1 << " " << m << " " << year << "\n";
}
int main()
{

    int day = 23, year = 1914;
    string m = "July";

    sherlockAndDate(day, year, m);

    return 0;
}