Calendar Application in C

The Calendar in C Programming is a Calendar Project In C that helps you find the date and day you need by being built in the C programming language. It also does a few other tasks. A C-written calendar application may offer information going back to the late 1600s. By just entering the values, you may also get the results for the day. Another choice is to include notes. The note area can include a maximum of 50 characters.

Describe the Calendar

It is a day-planning technique. This is done by giving names to certain time periods, most frequently days, weeks, months, and years. A date in such a system designates a single, particular day. A calendar is a tangible representation of such a system (typically made of paper). A calendar can also refer to a list of forthcoming occasions, such as a court calendar, or a collection of documents that are largely or entirely chronological, such as a wills calendar.

Program Breakdown

struct Date {
    int dd ;
    int mm ;
    int yy ;
} ;

We are creating a class for date having private data members as date month and year.

struct Remainder {
    int dd ;
    int mm ;
    char note [ 50 ] ;
} ;

We are creating a class for remainder having private data members as date, mounth and a character array note.

void SetColor ( int ForgC )
{
     WORD wColor ;
     //We will need this handle to get the current background attribute
     HANDLE hStdOut = GetStdHandle ( STD_OUTPUT_HANDLE ) ;
     CONSOLE_SCREEN_BUFFER_INFO csbi ;

     //We use csbi for the wAttributes word.
     if ( GetConsoleScreenBufferInfo ( hStdOut , & csbi ) )
     {
        //Mask out all but the background attribute, and add in the forgournd color
          wColor = ( csbi.wAttributes & 0xF0 ) + (ForgC & 0x0F ) ;
          SetConsoleTextAttribute ( hStdOut , wColor ) ;
     }
     return ;
} 

This will set the forground color for printing in a console window.

void ClearConsoleToColors ( int ForgC , int BackC )
{
     WORD wColor = ( ( BackC & 0x0F ) < < 4 ) + ( ForgC & 0x0F ) ;
     //Get the handle to the current output buffer ...
     HANDLE hStdOut = GetStdHandle ( STD_OUTPUT_HANDLE ) ;
     //This is used to reset the carat/cursor to the top left.
     COORD coord = { 0 , 0 } ;
     //A return value ... indicating how many chars were written
     //   not used but we need to capture this since it will be
     //   written anyway ( passing NULL causes an access violation ).
     DWORD count ;
     //This is a structure containing all of the console info
     // it is used here to find the size of the console.
     CONSOLE_SCREEN_BUFFER_INFO csbi ;
     //Here we will set the current color
     SetConsoleTextAttribute ( hStdOut , wColor ) ;
     if ( GetConsoleScreenBufferInfo ( hStdOut , & csbi ) )
     {
          //This fills the buffer with a given character (in this case 32=space).
          FillConsoleOutputCharacter ( hStdOut , ( TCHAR ) 32 , csbi . dwSize . X * csbi.dwSize.Y , coord , &count ) ;
          FillConsoleOutputAttribute ( hStdOut , csbi . wAttributes , csbi . dwSize . X * csbi . dwSize . Y , coord , & count ) ;
          //This will set our cursor position for the next print statement.
          SetConsoleCursorPosition ( hStdOut , coord ) ;
     }
     return ;
}

This is a structure containing all of the console info it is used here to find the size of the console.

void SetColorAndBackground ( int ForgC , int BackC )
{
     WORD wColor = ( ( BackC & 0x0F ) < < 4 ) + ( ForgC & 0x0F ) ;
     SetConsoleTextAttribute ( GetStdHandle ( STD_OUTPUT_HANDLE ) , wColor ) ;
     return ;
}

The above function is used to set the background color of the console.

int check_leapYear ( int year ) {  //checks whether the year passed is leap year or not
    if ( year % 400 = = 0 || ( year % 100 ! = 0 & & year % 4 = =0 ) )
       return 1 ;
    return 0 ;
}

The above peace of code is used to check if the user entered the year is a leap year or not.

int getNumberOfDays ( int month , int year ){ //returns the number of days in given month
   switch ( month ) {                          //and year
      case 1 : return ( 31 ) ;
      case 2 : if ( check_leapYear ( year ) = = 1 )
		 return ( 29 ) ;
	       else
		 return ( 28 ) ;
      case 3 : return ( 31 ) ;
      case 4 : return ( 30 ) ;
      case 5 : return ( 31 ) ;
      case 6 : return ( 30 ) ;
      case 7 : return ( 31 ) ;
      case 8 : return ( 31 ) ;
      case 9 : return ( 30 ) ;
      case 10 : return ( 31 ) ;
      case 11 : return ( 30 ) ;
      case 12 : return ( 31 ) ;
      default : return ( -1 ) ;
   }
}

The above function will return the number of days in the month.

char * getName ( int day ) { //returns the name of the day
   switch ( day ) {
      case 0 : return ( " Sunday " ) ;
      case 1 : return ( " Monday " ) ;
      case 2 : return ( " Tuesday " ) ;
      case 3 : return ( " Wednesday " ) ;
      case 4 : return ( " Thursday " ) ;
      case 5 : return ( " Friday " ) ;
      case 6 : return ( " Saturday " ) ;
      default : return ( " Error in getName ( ) module.Invalid argument passed " ) ;
   }
}

The above function is responsible to return the name of the day.

void AddNote ( ) {
    FILE * fp ;
    fp = fopen ( " note.dat " , " ab+ " ) ;
    system ( " cls " ) ;
    gotoxy ( 5 ,7 ) ;
    printf ( " Enter the date ( DD / MM ) : " ) ; 
    scanf ( " % d % d " , & R . dd , & R . mm ) ;
    gotoxy ( 5 , 8 ) ;
    printf ( " Enter the Note ( 50 character max ) : " ) ;
    fflush ( stdin ) ;
    scanf ( " % [ ^ \ n ] " , R.note ) ;
    if ( fwrite ( & R , sizeof ( R ) , 1 , fp ) ) {
        gotoxy ( 5 , 12 ) ;
        puts ( " Note is saved sucessfully " ) ;
        fclose ( fp ) ;
    }else {
        gotoxy ( 5 , 12 ) ;
        SetColor ( 12 ) ;
        puts ( " \ a Fail to save!! \ a " ) ;
        ClearColor ( ) ;
    }
    gotoxy ( 5 , 15 ) ;
    printf ( " Press any key............" ) ;
    getch ( ) ; 
    fclose ( fp ) ;
}

If a user wants to add a note at some particular date then it will be done by the above mentioned function.

void showNote ( int mm ) {
    FILE * fp ;
    int i = 0 , isFound = 0 ;
    system ( " cls " ) ;
    fp = fopen ( " note . dat " , " rb " ) ;
    if ( fp = = NULL ) {
        printf ( " Error in opening the file " ) ;
    }
    while ( fread ( &R , sizeof ( R ) , 1 , fp ) = = 1 ) {
        if ( R.mm = = mm ) {
            gotoxy ( 10 , 5 + i ) ;
            printf ( " Note % d Day = % d : % s " , i + 1 , R . dd ,  R . note ) ;
            isFound = 1 ;
            i + + ;
        }
    }
    if ( isFound = = 0 ) {
        gotoxy ( 10 ,5 ) ;
        printf ( " This Month contains no note " ) ;
    }
    gotoxy ( 10 , 7 + i ) ;
    printf ( " Press any key to back....... " ) ;
    getch ( ) ; 

}

The above function is used to show the note added by the user.

Program for Calendar Application in C

#include<stdio.h>
#include<conio.h>
#include<windows.h>

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct Date{
    int dd;
    int mm;
    int yy;
};
struct Date date;

struct Remainder{
    int dd;
    int mm;
    char note[50];
};
struct Remainder R;

COORD xy = {0, 0};

void gotoxy (int x, int y)
{
        xy.X = x; xy.Y = y; // X and Y coordinates
        SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), xy);
}
//This will set the forground color for printing in a console window.
void SetColor(int ForgC)
{
     WORD wColor;
     //We will need this handle to get the current background attribute
     HANDLE hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
     CONSOLE_SCREEN_BUFFER_INFO csbi;

     //We use csbi for the wAttributes word.
     if(GetConsoleScreenBufferInfo(hStdOut, &csbi))
     {
        //Mask out all but the background attribute, and add in the forgournd color
          wColor = (csbi.wAttributes & 0xF0) + (ForgC & 0x0F);
          SetConsoleTextAttribute(hStdOut, wColor);
     }
     return;
}

void ClearColor(){
    SetColor(15);
}

void ClearConsoleToColors(int ForgC, int BackC)
{
     WORD wColor = ((BackC & 0x0F) << 4) + (ForgC & 0x0F);
     //Get the handle to the current output buffer...
     HANDLE hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
     //This is used to reset the carat/cursor to the top left.
     COORD coord = {0, 0};
     //A return value... indicating how many chars were written
     //   not used but we need to capture this since it will be
     //   written anyway (passing NULL causes an access violation).
     DWORD count;

     //This is a structure containing all of the console info
     // it is used here to find the size of the console.
     CONSOLE_SCREEN_BUFFER_INFO csbi;
     //Here we will set the current color
     SetConsoleTextAttribute(hStdOut, wColor);
     if(GetConsoleScreenBufferInfo(hStdOut, &csbi))
     {
          //This fills the buffer with a given character (in this case 32=space).
          FillConsoleOutputCharacter(hStdOut, (TCHAR) 32, csbi.dwSize.X * csbi.dwSize.Y, coord, &count);

          FillConsoleOutputAttribute(hStdOut, csbi.wAttributes, csbi.dwSize.X * csbi.dwSize.Y, coord, &count );
          //This will set our cursor position for the next print statement.
          SetConsoleCursorPosition(hStdOut, coord);
     }
     return;
}

void SetColorAndBackground(int ForgC, int BackC)
{
     WORD wColor = ((BackC & 0x0F) << 4) + (ForgC & 0x0F);;
     SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), wColor);
     return;
}
int check_leapYear(int year){ //checks whether the year passed is leap year or not
    if(year % 400 == 0 || (year % 100!=0 && year % 4 ==0))
       return 1;
    return 0;
}
void increase_month(int *mm,  int *yy){ //increase the month by one
    ++*mm;
    if(*mm > 12){
        ++*yy;
        *mm = *mm - 12;
    }
}

void decrease_month(int *mm,  int *yy){ //decrease the month by one
    --*mm;
    if(*mm < 1){
        --*yy;
        if(*yy<1600){
            printf("No record available");
            return;
        }
        *mm = *mm + 12;
    }
}

int getNumberOfDays(int month,int year){ //returns the number of days in given month
   switch(month){                          //and year
      case 1 : return(31);
      case 2 : if(check_leapYear(year)==1)
         return(29);
           else
         return(28);
      case 3 : return(31);
      case 4 : return(30);
      case 5 : return(31);
      case 6 : return(30);
      case 7 : return(31);
      case 8 : return(31);
      case 9 : return(30);
      case 10: return(31);
      case 11: return(30);
      case 12: return(31);
      default: return(-1);
   }
}

char *getName(int day){ //returns the name of the day
   switch(day){
      case 0 :return("Sunday");
      case 1 :return("Monday");
      case 2 :return("Tuesday");
      case 3 :return("Wednesday");
      case 4 :return("Thursday");
      case 5 :return("Friday");
      case 6 :return("Saturday");
      default:return("Error in getName() module.Invalid argument passed");
   }
}

void print_date(int mm, int yy){ //prints the name of month and year
    printf("---------------------------\n");
    gotoxy(25,6);
    switch(mm){
        case 1: printf("January"); break;
        case 2: printf("February"); break;
        case 3: printf("March"); break;
        case 4: printf("April"); break;
        case 5: printf("May"); break;
        case 6: printf("June"); break;
        case 7: printf("July"); break;
        case 8: printf("August"); break;
        case 9: printf("September"); break;
        case 10: printf("October"); break;
        case 11: printf("November"); break;
        case 12: printf("December"); break;
    }
    printf(" , %d", yy);
    gotoxy(20,7);
    printf("---------------------------");
}
int getDayNumber(int day,int mon,int year){ //retuns the day number
    int res = 0, t1, t2, y = year;
    year = year - 1600;
    while(year >= 100){
        res = res + 5;
        year = year - 100;
    }
    res = (res % 7);
    t1 = ((year - 1) / 4);
    t2 = (year-1)-t1;
    t1 = (t1*2)+t2;
    t1 = (t1%7);
    res = res + t1;
    res = res%7;
    t2 = 0;
    for(t1 = 1;t1 < mon; t1++){
        t2 += getNumberOfDays(t1,y);
    }
    t2 = t2 + day;
    t2 = t2 % 7;
    res = res + t2;
    res = res % 7;
    if(y > 2000)
        res = res + 1;
    res = res % 7;
    return res;
}

char *getDay(int dd,int mm,int yy){
    int day;
    if(!(mm>=1 && mm<=12)){
        return("Invalid month value");
    }
    if(!(dd>=1 && dd<=getNumberOfDays(mm,yy))){
        return("Invalid date");
    }
    if(yy>=1600){
        day = getDayNumber(dd,mm,yy);
        day = day%7;
        return(getName(day));
    }else{
        return("Please give year more than 1600");
    }
}

int checkNote(int dd, int mm){
    FILE *fp;
    fp = fopen("note.dat","rb");
    if(fp == NULL){
        printf("Error in Opening the file");
    }
    while(fread(&R,sizeof(R),1,fp) == 1){
        if(R.dd == dd && R.mm == mm){
            fclose(fp);
            return 1;
        }
    }
    fclose(fp);
    return 0;
}

void printMonth(int mon,int year,int x,int y){ //prints the month with all days
    int nod, day, cnt, d = 1, x1 = x, y1 = y, isNote = 0;
    if(!(mon>=1 && mon<=12)){
        printf("INVALID MONTH");
        getch();
        return;
    }
    if(!(year>=1600)){
        printf("INVALID YEAR");
        getch();
        return;
    }
    gotoxy(20,y);
    print_date(mon,year);
    y += 3;
    gotoxy(x,y);
    printf("S   M   T   W   T   F   S   ");
    y++;
    nod = getNumberOfDays(mon,year);
    day = getDayNumber(d,mon,year);
    switch(day){ //locates the starting day in calender
        case 0 :
            x=x;
            cnt=1;
            break;
        case 1 :
            x=x+4;
            cnt=2;
            break;
        case 2 :
            x=x+8;
            cnt=3;
            break;
        case 3 :
            x=x+12;
            cnt=4;
            break;
        case 4 :
            x=x+16;
            cnt=5;
            break;
        case 5 :
            x=x+20;
            cnt=6;
            break;
        case 6 :
            x=x+24;
            cnt=7;
            break;
        default :
            printf("INVALID DATA FROM THE getOddNumber()MODULE");
            return;
    }
    gotoxy(x,y);
    if(cnt == 1){
        SetColor(12);
    }
    if(checkNote(d,mon)==1){
            SetColorAndBackground(15,12);
    }
    printf("%02d",d);
    SetColorAndBackground(15,1);
    for(d=2;d<=nod;d++){
        if(cnt%7==0){
            y++;
            cnt=0;
            x=x1-4;
        }
        x = x+4;
        cnt++;
        gotoxy(x,y);
        if(cnt==1){
            SetColor(12);
        }else{
            ClearColor();
        }
        if(checkNote(d,mon)==1){
            SetColorAndBackground(15,12);
        }
        printf("%02d",d);
        SetColorAndBackground(15,1);
    }
    gotoxy(8, y+2);
    SetColor(14);
    printf("Press 'n'  to Next, Press 'p' to Previous and 'q' to Quit");
    gotoxy(8,y+3);
    printf("Red Background indicates the NOTE, Press 's' to see note: ");
    ClearColor();
}

void AddNote(){
    FILE *fp;
    fp = fopen("note.dat","ab+");
    system("cls");
    gotoxy(5,7);
    printf("Enter the date(DD/MM): ");
    scanf("%d%d",&R.dd, &R.mm);
    gotoxy(5,8);
    printf("Enter the Note(50 character max): ");
    fflush(stdin);
    scanf("%[^\n]",R.note);
    if(fwrite(&R,sizeof(R),1,fp)){
        gotoxy(5,12);
        puts("Note is saved sucessfully");
        fclose(fp);
    }else{
        gotoxy(5,12);
        SetColor(12);
        puts("\aFail to save!!\a");
        ClearColor();
    }
    gotoxy(5,15);
    printf("Press any key............");
    getch();
    fclose(fp);
}

void showNote(int mm){
    FILE *fp;
    int i = 0, isFound = 0;
    system("cls");
    fp = fopen("note.dat","rb");
    if(fp == NULL){
        printf("Error in opening the file");
    }
    while(fread(&R,sizeof(R),1,fp) == 1){
        if(R.mm == mm){
            gotoxy(10,5+i);
            printf("Note %d Day = %d: %s", i+1, R.dd,  R.note);
            isFound = 1;
            i++;
        }
    }
    if(isFound == 0){
        gotoxy(10,5);
        printf("This Month contains no note");
    }
    gotoxy(10,7+i);
    printf("Press any key to back.......");
    getch();

}

int main(){
    ClearConsoleToColors(15, 5);
    SetConsoleTitle("Calender Project - ITSOURCECODE.COM");
    int choice;
    char ch = 'a';
    while(1){
        system("cls");
        printf("1. Find Out the Day\n");
        printf("2. Print all the day of month\n");
        printf("3. Add Note\n");
        printf("4. EXIT\n");
        printf("ENTER YOUR CHOICE : ");
        scanf("%d",&choice);
        system("cls");
        switch(choice){
            case 1:
                printf("Enter date (DD MM YYYY) : ");
                scanf("%d %d %d",&date.dd,&date.mm,&date.yy);
                printf("Day is : %s",getDay(date.dd,date.mm,date.yy));
                printf("\nPress any key to continue......");
                getch();
                break;
            case 2 :
                printf("Enter month and year (MM YYYY) : ");
                scanf("%d %d",&date.mm,&date.yy);
                system("cls");
                while(ch!='q'){
                    printMonth(date.mm,date.yy,20,5);
                    ch = getch();
                    if(ch == 'n'){
                        increase_month(&date.mm,&date.yy);
                        system("cls");
                        printMonth(date.mm,date.yy,20,5);
                    }else if(ch == 'p'){
                        decrease_month(&date.mm,&date.yy);
                        system("cls");
                        printMonth(date.mm,date.yy,20,5);
                    }else if(ch == 's'){
                        showNote(date.mm);
                        system("cls");
                    }
                }
                break;
            case 3:
                AddNote();
                break;
            case 4 :
                exit(0);
        }
    }
    return 0;
}

Output:

. Find Out the Day
2. Print all the day of month
3. Add Note
4. EXIT
ENTER YOUR CHOICE :1
Enter date (DD MM YYYY) : 22 08 2022
ENTER YOUR CHOICE :2
---------------------------
                         August , 2022
                    ---------------------------
                    S   M   T   W   T   F   S
                        01  02  03  04  05  06
                    07  08  09  10  11  12  13
                    14  15  16  17  18  19  20
                    21  22  23  24  25  26  27
                    28  29  30  31

        Press 'n'  to Next, Press 'p' to Previous and 'q' to Quit
        Red Background indicates the NOTE, Press 's' to see note:
ENTER YOUR CHOICE: 3
Enter the date(DD/MM): 22 08
     Enter the Note(50 character max): All you need is JavaTpoint
     Note is saved sucessfully
     Press any key............
--------------------------------
Process exited after 393.4 seconds with return value 0
Press any key to continue . . .

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