從鍵盤輸入年、月、日。在屏幕輸出此日期是該年的第幾天。

源程序：

#include<stdio.h> int Leap(int year)                                         //判斷輸入年份是否為閏年{    if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))    {        return 1;    }    else    {        return 0;    }} int number(int year, int month, int day){    int sum = 0;    int a[12] = { 31, 29, 31, 30.31, 30, 31, 31, 30, 31, 30, 31};   //閏年每月的天數(shù)    int b[12] = { 31, 28, 31, 30.31, 30, 31, 31, 30, 31, 30, 31};   //平年每月對應(yīng)的天數(shù)     switch (Leap(year))    {    case 1:        for (int i = 0; i < month - 1; i++)        {            sum += a[i];        }        break;    case 0:        for (int i = 0; i < month - 1; i++)        {            sum += b[i];        }        break;    }    sum += day;    return sum;}int main(){    int year, month, day;    int sum = 0;    printf("請輸入一個(gè)日期：\n");    scanf("%d%d%d", &year, &month, &day);    sum = number(year, month, day);    printf("\n");    printf("該日期為%-4d年第%-3d天\n", year, sum);    return 0;}