Sure, here's a simple C program that prompts a user for a number of days and converts that into hours, minutes, and seconds:
C:
#include <stdio.h>
int main()
{
int days;
long int hours, minutes, seconds;
printf("Enter the number of days: ");
scanf("%d", &days);
// converting days to hours, minutes and seconds
hours = days * 24;
minutes = hours * 60;
seconds = minutes * 60;
printf("In %d days there are: \n", days);
printf("%ld hours \n", hours);
printf("%ld minutes \n", minutes);
printf("%ld seconds \n", seconds);
return 0;
}
In this program, the user is first asked to enter the number of days. This input is stored in the variable 'days'. The program then calculates the equivalent number of hours, minutes, and seconds by multiplying the number of days by 24 (to get hours), the number of hours by 60 (to get minutes), and the number of minutes by 60 (to get seconds). Finally, the program prints out the results.