コード
#include <stdio.h>
typedef struct {
int y;
int m;
int d;
} Date;
Date DateOf(int y, int m, int d);
Date After(Date x, int n);
Date Before(Date x, int n);
int isleap(int year);
int main(void)
{
int y, m, d, a, b;
Date test_day;
Date after_day;
Date before_day;
y = 2018;
m = 9;
d = 20;
printf("日付を何日進めますか？：");
scanf("%d", &a);
printf("日付を何日戻しますか？：");
scanf("%d", &b);
test_day = DateOf(y, m, d);
after_day = After(test_day, a);
before_day = Before(test_day, b);
printf("%d年%d月%d日ですね。\n", test_day.y, test_day.m, test_day.d);
printf("--- 日付を進めると ---\n");
printf("%d年%d月%d日ですね。\n", after_day.y, after_day.m, after_day.d);
printf("--- 日付を戻すと ---\n");
printf("%d年%d月%d日ですね。\n", before_day.y, before_day.m, before_day.d);
return 0;
}
Date DateOf(int y, int m, int d)
{
Date today;
today.y = y;
today.m = m;
today.d = d;
return today;
}
Date After(Date x, int n)
{
int uru_flg;
int loop_end_cnt = 0;
x.d += n;
while(loop_end_cnt == 0){
uru_flg = isleap(x.y);
if(x.m == 1 || x.m == 3 || x.m == 5 || x.m == 7 || x.m == 8 || x.m == 10 || x.m == 12){
if(x.d <= 31){
loop_end_cnt = 1;
}
if(x.d > 31){
x.d = x.d - 31;
x.m += 1;
}
}else if(x.m == 4 || x.m == 6 || x.m == 9 || x.m == 11){
if(x.d <= 30){
loop_end_cnt = 1;
}
if(x.d > 30){
x.d = x.d - 30;
x.m += 1;
}
}else if(x.m == 2){
if(uru_flg == 0){
if(x.d <= 28){
loop_end_cnt = 1;
}
if(x.d > 28){
x.d = x.d - 28;
x.m += 1;
}
}else if(uru_flg == 1){
if(x.d <= 29){
loop_end_cnt = 1;
}
if(x.d > 29){
x.d = x.d - 29;
x.m += 1;
}
}
}
if(x.m == 13){
x.y += 1;
x.m = 1;
}
}
return x;
}
int isleap(int year)
{
}
Date Before(Date x, int n)
{
int uru_flg;
int loop_end_cnt = 0;
x.d -= n;
while(loop_end_cnt == 0){
uru_flg = isleap(x.y);
if(x.m == 1 || x.m == 3 || x.m == 5 || x.m == 7 || x.m == 8 || x.m == 10 || x.m == 12){
if(x.d >= 1){
loop_end_cnt = 1;
}
if(x.d < 1){
x.d = x.d + 31;
x.m -= 1;
}
}else if(x.m == 4 || x.m == 6 || x.m == 9 || x.m == 11){
if(x.d >= 1){
loop_end_cnt = 1;
}
if(x.d < 1){
x.d = x.d + 30;
x.m -= 1;
}
}else if(x.m == 2){
if(x.d > 1){
loop_end_cnt = 1;
}
if(uru_flg == 0){
if(x.d < 1){
x.d = x.d + 28;
x.m -= 1;
}
}else if(uru_flg == 1){
if(x.d < 1){
x.d = x.d + 29;
x.m -= 1;
}
}
}
if(x.m == 0){
x.y -= 1;
x.m = 12;
}
}
return x;
}
所感
完成！！いやーなかなか難しかった。n日後とn日前を求める問題。
久しぶりにノートを取り出して設計をかんがえた。でも楽しかった。
*1:year % 4 == 0) && (year % 100 != 0
