1-Write a program that determines the day number (1 to 366) in a year for a date that

Question

provided as input data. As an example, January 1, 1994, is day 1. December 31, 1994, is
day 365. December 31, 1996, is day 366, since 1996 is a leap year. A year is a leap year
if it is divisible by four, except that any year divisible by 100 is a leap year only if it is
divisible by 400. Your program should accept the month, day, and year as integers.
2-The table shows the normal boiling points of several substances. Write a program that
prompts the user for the observed boiling point of a substance in ºC and identifies the
substance if the observed boiling point is within 5% of the expected boiling point. If the
data input is more than 5% higher or lower than any of the boiling points in the table, the
program should output message “Substance unknown”.
Substance Normal boiling point (ºC)
Water 100
Mercury 357
Copper 1187
Silver 2193
Gold 2660

Answer 1

#include <stdio.h>

int isleap(int year);

void displaydate(int month ,int date ,int year,int daynumber);

int main (void) {

int month;
int day;
int year;
int leapyear;
int daynumber;

printf(" enter a month");
scanf("%d",&month);

printf(" enter a day");
scanf("%d",&day);

printf(" enter a year");
scanf("%d",&year);

leapyear= isleap( year);

displaydate( month,day,year,daynumber);

daynumber = leapyear && month > 2 ? day+1 : day;

switch(month) {

case 1 : daynumber = day;
break;

case 2 : daynumber = 31 + day;
break;

case 3 : daynumber = 59 + day + 1;
break;

case 4 : daynumber = 89 + day;
break;

case 5 : daynumber = 120 + day;
break;

case 6 : daynumber = 150 + day;
break;

case 7 : daynumber = 181 + day;
break;

case 8 : daynumber = 212 + day;
break;

case 9 : daynumber = 232 + day;
break;

case 10 : daynumber = 263 + day;
break;

case 11 : daynumber = 293 + day;
break;

case 12 : daynumber = 324 + day;
break;

default:
break;
}

return 0;
}

int isleap(int year)
{
if (((year % 4 == 0) && (year % 100!= 0)) || (year%400 == 0)) {
printf("%d 1", year);
return 1;
}
else {
printf("%d 0", year);
return 0;
}
}

void displaydate(int month ,int date ,int year,int daynumber)
{
printf("\n your date is %d and the day number is %d",month,date,year,daynumber);

}