C++ //习题 7.2 写一个函数days，实现上面的计算。由主函数将年、月、日传递给函数days，计算后将日子数传回主函数输出。

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C++程序设计（第三版）谭浩强习题7.2

习题 7.2 写一个函数days，实现上面的计算。由主函数将年、月、日传递给函数days，计算后将日子数传回主函数输出。

IDE工具：VS2010

Note: 使用不同的IDE工具可能有部分差异。

代码块

方法：使用指针，结构体，自定义类型，函数的模块化设计，分配内存

#include <iostream>
using namespace std;typedef struct{int year;int month;int day;
}Date;bool isLeapYear(int year){return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0 ? true : false;
}bool isRightMonth(int month){return month < 1 || month > 12 ? false : true;
}bool isRightDay(int year, int month, int day){if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month ==12){return day >= 1 && day <= 31 ? true : false;}else if(month == 4 || month == 6 || month == 9 || month == 11){return day >= 1 && day <= 30 ? true : false;}else{if(isLeapYear(year) == true){return day >= 1 && day <= 29 ? true : false;}else{return day >= 1  && day <= 28 ? true : false;}}
}void inputDate(Date *date){cout<<"Enter Year: ";cin>>date->year;while(date->year <= 0 || date->year > 9999){cout<<"Year Error! Retry!\nEnter Year: ";cin>>date->year;}cout<<"Enter Month: ";cin>>date->month;while(isRightMonth(date->month) == false){cout<<"Month Error! Retry!\nEnter Month: ";cin>>date->month;}cout<<"Enter Day: ";cin>>date->day;while(isRightDay(date->year, date->month, date->day) == false){cout<<"Day Error! Retry!\nEnter Day: ";cin>>date->day;}cout<<endl;
}int days(Date *date){int sum = 0;for(int i = 1; i < date->month; i++){if(i == 1 || i == 3 || i == 5 || i == 7 || i == 8 || i == 10 || i ==12){sum += 31;}else if(i == 4 || i == 6 || i == 9 || i == 11){sum += 30;}else{if(isLeapYear(date->year) == true){sum += 29;}else{sum += 28;}}}sum += date->day;return sum;
}int main(){Date *date = new Date;inputDate(date);cout<<"The day is No."<<days(date)<<" days in "<<date->year<<"."<<endl;delete(date);system("pause");return 0;
}