Clock Application

This program takes user input for a time in HH:MM format, validates the input, and then determines which time-related phrases should be included in the output based on the entered time. The final result is printed on the console.

#include<stdio.h>
#include<stdlib.h>
main()
{
 char *temp[]={"Half","Ten","Quarter","Twenty","Five","Minutes","To","Past","One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Eleven","Twelve","O' Clock"};
 char time[5],substr[3][3];
 int i=0,j=0,k=0,hour,min,s[21]={0};
 printf("Enter time in HH:MM format like 01:15 in 12 hour format\n");
    gets(time);

    while(time[k]!='\0')
    {
        j=0;
        while(time[k]!=':'&&time[k]!='\0')
        {
            substr[i][j]=time[k];
            k++;
            j++;
        }
        substr[i][j]='\0';
        i++;
        if(time[k]!='\0')
        {
            k++;
        }
    }
    int len=i;
  hour=atoi(substr[0]);
  min=atoi(substr[1]);
  if(hour<1||hour>12||min<0||min>59)
  {
   printf("Enter Valid Time\n");
   exit(0);
  }
  else
  {
   if((min>=5&&min<10)||(min>=55&&min<=59))
   {
    s[4]=1;
   }
   if((min>=10&&min<15)||(min>=50&&min<55))
   {
    s[1]=1;
   }
   if((min>=15&&min<20)||(min>=45&&min<50))
   {
    s[2]=1;
   }
   if((min>=20&&min<25)||(min>=40&&min<45))
   {
    s[3]=1;
   }
   if(min>=25&&min<40)
   {
    s[0]=1;
   }
   if(min>=1&&min<=30)
   {
    if(min>=5)
    {
     s[7]=1;
    }
    s[hour+7]=1;
   }
  if(min>30&&min<=59)
   {
    s[6]=1;
    if(s[2]!=1)
    {
          s[5]=1;
    }
    if(hour!=12)
    s[hour+8]=1;
    else
    s[8]=1;
   }
   if(min>=0&&min<5)
   {
    s[hour+7]=1;
    s[20]=1;
   }

  }
  for(i=0;i<21;i++)
  {
   if(s[i]==1)
   {
    printf("%s ",temp[i]);
   }
  }
  printf("\n");
}

Enter time in HH:MM format like 01:15 in 12 hour format
2:15
Quarter Past Two

Let’s break down the code step by step:

1. Include Header Files:

   #include<stdio.h>
   #include<stdlib.h>

These are standard C library header files. <stdio.h> is for input/output functions, and <stdlib.h> for memory allocation functions.

2. Main Function:

   main()
   {

In older C standards, the main() function is used without specifying the return type (implicitly considered int).

3. Declare Arrays and Variables:

   char *temp[] = {"Half","Ten","Quarter","Twenty","Five","Minutes","To","Past","One","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Eleven","Twelve","O' Clock"};
   char time[5], substr[3][3];
   int i = 0, j = 0, k = 0, hour, min, s[21] = {0};

Arrays are declared to store strings and integers. temp[] holds strings representing various time-related phrases, and s[] is an array of flags to indicate which phrases to include in the final output. Variables are declared to store time components and loop indices.

4. User Input:

   printf("Enter time in HH:MM format like 01:15 in 12-hour format\n");
   gets(time);

The user is prompted to input the time in the format HH:MM, representing hours and minutes in a 12-hour clock format. gets() is used to read the input string.

5. Extract Hours and Minutes:

   while (time[k] != '\0')
   {
       j = 0;
       while (time[k] != ':' && time[k] != '\0')
       {
           substr[i][j] = time[k];
           k++;
           j++;
       }
       substr[i][j] = '\0';
       i++;
       if (time[k] != '\0')
       {
           k++;
       }
   }

The code parses the input string to extract hours and minutes by splitting at the colon ‘:‘.

6. Convert to Integers:

   int len = i;
   hour = atoi(substr[0]);
   min = atoi(substr[1]);

Converts the extracted substrings to integers using atoi().

7. Check for Valid Time:

   if (hour < 1 || hour > 12 || min < 0 || min > 59)
   {
       printf("Enter Valid Time\n");
       exit(0);
   }

Checks if the entered hour and minute values are within valid ranges. If not, prints an error message and exits the program.

8. Determine Time Phrases:

   else
   {
      s[] array based on the minutes and hours.
   }

Based on the entered time, sets flags in the s[] array to indicate which time-related phrases to include in the output.

9. Print Result:

   for (i = 0; i < 21; i++)
   {
       if (s[i] == 1)
       {
           printf("%s ", temp[i]);
       }
   }
   printf("\n");

Prints the time-related phrases corresponding to the set flags in the s[ ] array.

10. Close Main Function:

}

Closes the main function.