C 把年龄转换为天数
计算从出生年到现在的天数（假设出生日期是*年1月1日）
代码如下：
AgeToDay.cpp
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/*AgeToDay.cpp -- 把自己的年龄转换成天数*/#include<stdio.h>#include<time.h>#include<stdlib.h>#define RUNYEAR 366 //闰年天数#define PINGYEAR 365 //平年天数int getThisYear(); //得到当前年份 char year[]表示指向char类型的指针bool isRunYear(int year); //判断是否是闰年int getDays(int year,int age,int days); //得到天数int getNowDays(); //得到今天是今年的第几天int main(void){int year;//今年int myAge;//年龄int days;//得到今天是今年的第几天int allDays;year = getThisYear(); //得到当前年份days = getNowDays(); printf("Please enter your age:"); if(scanf("%d",&myAge) == 1 && myAge > 0 && myAge < 150){ allDays = getDays(year,myAge,days); printf("the days you have gone is : %d\n",allDays);}else{printf("输入格式错误!\n");} return 0;}//得到当前系统年份int getThisYear() {struct tm *nowtime; //时间结构time_t local_time; //本地时间 char year[5]; //今年local_time = time(NULL);nowtime = localtime(&local_time);strftime(year,5,"%Y",nowtime); //转换成2001形式return atoi(year);}int getNowDays(){struct tm *nowtime;time_t local_time; char days[10]; local_time = time(NULL);nowtime = localtime(&local_time);strftime(days,10,"%j",nowtime);puts(days);return atoi(days);}//判断某年是否为闰年，若是则返回truebool isRunYear(int year){if((year % 4 ==0 && year % 100 !=0) || year % 400 == 0)return true;return false;}//得到从出生年到现在的天数（假设是1月1号出生）int getDays(int year,int age,int days){ int count = 0; //从当前年份到出生年份含有的闰年数int alldays;for(int i = year -1; i < year - age ; i-- ){if(isRunYear(i))count++;}alldays = RUNYEAR * count +PINGYEAR * (age - 1 - count) + days; return alldays;}