1. Write the function day_of_yrar(month,day,year) so that the day on which the function returns to be determined by these three parameters is the day of the year (integer between 1 and 365).
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int day(int mounth, int day,int year);
int main()
{
int mounth, days, year,sum;
printf("Input date: month/day/year");
scanf("%d / %d / %d", &mounth, &days, &year);
printf("The day is %d days of %d\n", day(mounth,days,year), year);
return 0;
}
int day(int mounth, int day,int year)
{
int num_days[] = { 31,28,31,30,31,30,31,31,30,31,30,31 };
int day_count = 0, i;
for (i = 1; i < mounth; i++) {
day_count += num_days[i - 1];
}
if (year % 4 == 0 && mounth > 2) {
day_count++;
}
return day_count + day;
}2. /* Writes the function num_digits(n) so that the function returns the number of digits in the positive integer n. Tip: In order to determine the number of numbers in n, divide the number by 10 repeatedly. When n=0, the number of divisions indicates the number of numbers that n initially owned.
/*Write the function num_digits(n) so that the function returns the number of numbers in the positive integer n. Tip: For confirmation
n When n=0, the number of divisions indicates the origin of n.
Number of numbers owned.*/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int function(int i);
int main()
{
int i;
printf("Enter a positive X Integer:");
scanf("%d", &i);
return function(i);
}
int function(int i)
{
int n = 0;
do {
i /= 10;
n++;
} while (i != 0);
return n;
}3. Write the function digit(n, k), so that the function returns the number k in the positive integer n (from the right). For example, digita (829, 1) returns 9, and digita (829, 3) returns 8. If K is greater than the number of numbers contained in n, return 0
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int function(int i ,int k);
int main()
{
int i,k;
printf("Enter a positive X Integer:");
scanf("%d %d", &i,&k);
return function(i,k);
}
int function(int i,int k)
{
int n = 0,j=0, a[100] = { 0 };
do {
a[j++] = i % 10;
i /= 10;
n++;
} while (i != 0);
if (k > n) {
return 0;
}
return a[k-1];
}4. Quick Sorting Algorithms
/* Sorts an arry of integers using Quicksort algorithm */
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#define N 10
void quicksort(int a[], int low, int high);
int split(int a[], int low, int high);
int main(void)
{
int a[N], i;
printf("Enter %d numbers to be sorted: ", N);
for (i = 0; i < N; i++) {
scanf("%d", &a[i]);
}
quicksort(a, 0,N - 1);
printf("In sorted order: ");
for (i = 0; i < N; i++) {
printf("%d ", a[i]);
}
printf("\n");
return 0;
}
void quicksort(int a[], int low, int high)
{
int middle;
if (low >= high) { return;}
middle = split(a, low, high);
quicksort(a, low, middle-1);
quicksort(a, middle + 1, high);
}
int split(int a[], int low, int high)
{
int part_element = a[low];
for (;;) {
while (low < high && part_element <= a[high]) { high--; }
if (low >= high) { break; }
a[low++] = a[high];
while (low < high && a[low] <= part_element) { low++; }
if (low >= high) { break; }
a[high--] = a[low];
}
a[high] = part_element;
return high;
}5. Time in seconds
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
void split_time(long total_sec, int* hr, int* min, int* sec);
int main(void)
{
long total_sec;
scanf("%d", &total_sec);
int* hr, * min, * sec, hour = 0, minute = 0, second = 0;
int day = 0;
if (total_sec < 24 * 3600) {
;
}
else {
day = total_sec/(24 * 3600);
total_sec = total_sec - day * 24 * 3600;
}
split_time(total_sec, &hour, &minute, &second);
printf("Output current corresponding time:%d day%2.2d:%2.2d:%2.2d\n", day,hour, minute, second);
return 0;
}
void split_time(long total_sec, int* hr, int* min, int* sec)
{
*hr = total_sec / 3600;
*min = (total_sec-*hr*3600)/60;
*sec = total_sec - *hr * 3600 - *min * 60;
}6. Find the first and second largest numbers in the array and display them.
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#define N 10
void find_largest(int a[N],int *largest,int *second_largest);
int main(void)
{
int a[N], * largest, * second_largest, max, second_max;
for (int i = 0; i < N; i++) {
scanf("%d", &a[i]);
}
find_largest( a, &max, &second_max);
printf("largesr==%d second==%d\n", max, second_max);
return 0;
}
void find_largest( int a[N], int *largest, int *second_largest)
{
*largest = *second_largest = a[0];
for (int i = 1; i < N; i++) {
if (a[i] > * largest) {
*largest = a[i];
}
}
for (int i = 1; i < N; i++) {
if (*second_largest < a[i] && a[i] < *largest) {
*second_largest = a[i];
}
}
}7. The Days of the Year
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
void split_date(int day_of_year, int* year, int* month, int* day);
int main(void)
{
int num_year, num_month, num_day, * year, * month, * day, day_of_year=0;
printf("Enter date: mm/dd/yy ");
scanf("%d/%d/%d", &num_year, &num_month, &num_day);
year = & num_year;
month = & num_month;
day = & num_day;
split_date(day_of_year, &num_year, &num_month, &num_day);
return 0;
}
void split_date(int day_of_year, int *year, int* month, int* day)
{
int num_days[] = { 31, 28, 31, 30, 31, 30, \
31, 31, 30, 31, 30, 31 };
int i;
for (i = 1; i < *month; i++) {
day_of_year += num_days[i-1];
}
if (*year % 4 == 0) { day_of_year++; }
printf("day_of_year:%d\n", day_of_year + *day);
}
8. Pass in an array of length a and return the pointer to the largest element of the array*p
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int* find_largest(int a[], int n);
int main(void)
{
int a[] = { 3, 28, 21, 32, 45, 55, 65, 32,5, 621, 80, 31 };
printf("%d\n", *find_largest(a, sizeof(a) / sizeof(a[0])));
return 0;
}
int* find_largest(int a[], int n)
{
int* p,max=a[0];
p = &max;
for (int i = 0; i < n; i++) {
if (max < a[i]) {
max = a[i];
}
else { ; }
}
return p;
}