C++ code to count columns for calendar with month and first day

Suppose we have two numbers m and d. Consider a calendar where week days are represented as columns and rows are current days. We want to know how many columns in the calendar should have given the month m and the weekday of the first date of that month d (Assuming that the year is not leap-year).

So, if the input is like m = 11; d = 6, then the output will be 5, because 1-st November is Saturday and 5 columns is enough.

Steps

To solve this, we will follow these steps −

Define an array a of size: 13 := { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
return (a[m] + d + 5) / 7

Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;
int solve(int m, int d){
   int a[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
   return (a[m] + d + 5) / 7;
}
int main(){
   int m = 11;
   int d = 6;
   cout << solve(m, d) << endl;
}

Input

11, 6

Output

5