题目要求：再加两个功能：正数计时和倒数计时
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#include<iostream>
#include<windows.h>
using namespace std;
class Time {
public:
int hour;
int minute;
int sec;
Time() {
int hour=0;
minute = 0;
sec = 0;
}
Time(int h,int m, int s):hour(h),minute(m), sec(s)
{}
Time& operator++();
Time& operator--();
friend Time& operator+=(Time& a, Time& b);
friend Time& operator-=(Time& a, Time& b);
void Print();
};
Time& Time::operator++() {
sec++;
if (sec >= 60) {
sec -= 60;
minute++;
if(minute>=60){
minute-=60;
hour++;
}
}
return *this;
}
Time& Time::operator--() {?
sec--;
if (sec < 0) {
sec += 60;
minute--;
if(minute<0){
minute+=60;
hour--;
}
}
return *this;
}
Time& operator+=(Time& a, Time& b) {
int hour;
int minute;
int sec;
if (a.sec + b.sec >= 60) {
a.sec += b.sec;
a.sec -= 60;
a.minute++;
}
else {
a.sec += b.sec;
}
if (a.minute + b.minute >= 60) {
a.minute += b.minute;
a.minute -= 60;
hour++;
}
else {
a.minute += b.minute;
}
a.hour+=b.hour;
return a;
}
Time& operator-=(Time& a, Time& b) {
int hour;
int minute;
int sec;
int t1, t2, t;
t1 = a.hour*60*60+ a.minute * 60 + a.sec;
t2 = b.hour*60*60+b.minute * 60 + b.sec;
if (t1 >= t2) {
t = t1 - t2;
}
else {
t = t2 - t1;
}
a.hour = t/3600;
a.minute = t%/60;
a.sec = t % 60;这里有问题，研究清楚后改正
return a;
}
void Time::Print() {
cout << "当前时间是：";
cout <<hour<<"时"<< minute << "分" << sec << "秒" << endl;
}
int main() {
Time time1, time2, time3;
int a;
cout << "请输入小时："<< endl;
cin ?>>time1.hour;
cout << "请输入分钟：" << endl;
cin >> time1.minute;
cout << "请输入秒钟：" << endl;
cin >> time1.sec;
cout << "当前时间是：" << time1.hour<<"时:"<<time1.minute << "分:" << time1.sec << "秒" << endl;
cout << "--------------------------------" << endl;
cout << "请输入操作" << endl << "1.整数计时" << endl << "2.倒数计时" << endl << "3.时间相加" << endl << "4.时间相减" << endl;
cout << "--------------------------------" << endl;
while (scanf("%d", &a) != EOF) {
switch (a) {
case 1:
for (int i = 0; i < 8; i++) {
++time1;
Sleep(1000);
time1.Print();
}
break;
case 2:
for (int i = 0; i < 8; i++) {
--time1;
Sleep(1000);
time1.Print();
}
break;
case 3:
cout << "请输入需要相加的时间（时钟）" << endl;
cin >> time2.hour;
cout << "请输入需要相加的时间（分钟）" << endl;
cin >> time2.minute;
cout << "请输入需要相加的时间（秒钟）" << endl;
cin >> time2.sec;
time1 += time2;
time1.Print();
break;
case 4:
cout << "请输入需要相减的时间（时钟）" << endl;
cin >> time3.hour;
cout << "请输入需要相减的时间（分钟）" << endl;
cin >> time3.minute;
cout << "请输入需要相减的时间（秒钟）" << endl;
cin >> time3.sec;
time1 -= time3;
time1.Print();
break;
}
}
return 0;
}
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