C Program : Display number of days in a calendar format of an entered month of a year 2001

Visualizing Calendar Days for the Year 2001 in C Programming

In this C programming exploration, we dive into a code snippet designed to display the number of days in a calendar format for a specified month of the year 2001. The program takes user input for the month, calculates the days, and organizes them in a calendar layout. Let's break down the code to understand its functionality.

The Code:

 #include<stdio.h>
 main()
  {
    int m, h, i = 1, a, j, b = 1;
    printf("\n Enter the month no. of year 2001 : ");
    scanf("%d", &m);
    switch(m)
     {
       case 1:          
          a = 2;
          j = 31;
          break;    
       
        case 2:          
          a = 5;
          j = 28;
          break;        

        case 3:          
          a = 5;
          j = 31;
          break;        
 
        case 4:          
          a = 1;
          j = 30;
          break;        

        case 5:          
          a = 3;
          j = 30;
          break;   
     
        case 6:          
          a = 6;
          j = 30;
          break;     

        case 7:          
          a = 1;
          j = 31;
          break;        
   
        case 8:          
          a = 4;
          j = 31;
          break;        

        case 9:          
          a = 7;
          j = 30;
          break;        

        case 10:          
          a = 2;
          j = 31;
          break;        

        case 11:          
          a = 5;
          j = 30;
          break;        

        case 12:          
          a = 7;
          j = 31;
          break;        

        default:           
          printf("\a\a Invalid Month ");
          break;
     }

    printf("\n\n");
    printf("\t\t Month %d of 2001\n\n", m);   
    printf("\t SUN \t MON \t TUE \t WED \t THR \t FRI \t SAT \n\n");
    switch(a)
     {
       case 1:
           printf("\t %d", i);
           break;

       case 2:
           printf("\t \t %d", i);
           break;

       case 3:
           printf("\t \t \t %d", i);
           break;

       case 4:
           printf("\t \t \t \t %d", i);
           break;

       case 5:
           printf("\t \t \t \t \t %d", i);
           break;

       case 6:
           printf("\t \t \t \t \t \t %d", i);
           break;

       case 7:
           printf("\t \t \t \t \t \t \t %d", i);
           break;
     }

   h = 8 - a;
   for(i = 2; i < = h; i++)
    printf("\t %d ", i);
    printf("\n");
    for(i = h + 1 ; i < = j; i++)
     {
       if(b == 8)
        {
          printf("\n");
          b = 1;
        }
       printf("\t %d", i);
       b++;
     }
  }
  

Explanation:

1. User Input:

   The program prompts the user to enter the month number of the year 2001.

2. Switch Statement:

   The code employs a switch statement to determine the number of days and the starting day of the week for the specified month.

3. Calendar Display:

   After determining the necessary details, the program prints a calendar for the specified month, organized by days of the week.

Input and Output Example:

Assuming the user enters 1 for January:

• Input : Enter the month of year 2001 : 1
• Output :

        Month 1 of 2001

 SUN    MON    TUE    WED    THR    FRI    SAT

         1      2      3      4      5     6
 7       8      9     10     11     12     13
14      15     16     17     18     19     20
21      22     23     24     25     26     27
28      29     30     31