2-10

C Crash Course/16 Sturcture&Union&Enum/stucture/prelesson/stucture-as-func-parameter/main.c

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+#include<stdbool.h>
+
+struct date {
+	int month;
+	int day;
+	int year;
+	//月 - 日 - 年 咱得国际化！
+};
+
+bool isleap(struct date d);//判断是否为闰年
+int NumberOfDays(struct date d);//判断天数
+bool ErrorInputCheck(struct date d);//检查是否是合法输入
+
+int main(void) {
+	
+	struct date today, tomorrow;
+	int flag = 0;
+
+	printf("Input today's date:(format: month day year)\n");
+	scanf("%d %d %d", &today.month, &today.day, &today.year);
+
+	if (ErrorInputCheck(today))
+		return 0;
+
+	if (today.day != NumberOfDays(today)) {
+
+		tomorrow = today;
+		tomorrow.day++;
+
+	}
+	else if (today.month != 12) {
+
+		tomorrow.day = 1;
+		tomorrow.month = today.month + 1;
+		tomorrow.year = today.year;
+
+	}
+	else {
+
+		tomorrow.day = 1;
+		tomorrow.month = 1;
+		tomorrow.year = today.year + 1;
+
+	}
+
+	printf("%d - %d - %d\n", tomorrow.month, tomorrow.day, tomorrow.year);
+
+	return 0;
+}
+
+bool ErrorInputCheck(struct date d) {
+	
+	bool flag = false;
+
+	if (d.day <= 0 || d.day > 31) {
+
+		printf("illegal input of day!\n");
+		flag = true;
+
+	}
+	if (d.month <= 0 || d.month > 12) {
+
+		printf("illegal input of month!\n");
+		flag = true;
+
+	}
+	if (d.year < 0) {
+
+		printf("illegal year!\n");
+		flag = true;
+
+	}
+
+	return flag;
+}
+
+int NumberOfDays(struct date d) {
+
+	int day = 0;
+	int days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+	if (d.month == 2 && isleap)
+		day = 29;
+	else
+		day = days[d.month - 1];
+
+	return day;
+}
+
+bool isleap(struct date d) {
+
+	bool leap = false;
+	int year = d.year;
+
+	if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
+		leap = true;
+
+	return leap;
+}

C Crash Course/16 Sturcture&Union&Enum/stucture/prelesson/stucture-as-func-parameter/readme.md

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+#### 结构体作为函数参数
+**明天的日期**
+*写一个程序:输入今天的日期,求明天的日期*
+
+看着这个问题简单,实际上稍微有点技巧.
+给出下面四个特殊日期,大家可以思考一下:
+
+>2020 - 1 -31
+>2020 - 11 - 31
+>2020 - 12 - 31
+>2000 - 2 - 28
+
+#### Use sturcture itself as a function's parameter
+it's not an efficient way
+
+>K & R said （p.131 ）
+>"if a large structure is to be passed to a function,
+>in is generally more efficent to pass a pointer than to copy the whole structure"