请问为什么我的代码在Devc++上运行正常，输出的结果也对，放到pta上就显示编译错误啊？

题目：定义一个时间类time,内有数据成员hour,minute,second，另有成员函数：构造函数用于初始化数据成员，输出函数，运算符重载+（加号），。编写主函数：创建时间对象，再输入秒数 n，通过运算符重载+（减号），计算该时间再过 n 秒后的时间值，时间的表示形式为时:分:秒，超过 24 时从 0 时重新开始计时。

　　测试输入包含若干测试用例，每个测试用例占一行。当读入0 0 0 0时输入结束，相应的结果不要输出。

　　　
　　　输入输出示例：括号内为说明

　　　0 0 1 59 (时间为0:0:1,秒数n=59)

　　　11 59 40 30 (时间为11:59:40,秒数n=30)

　　　23 59 40 3011 (时间为23:59:40,秒数n=3011)

　　　0 0 0 0

　　　输出：

  time:0:1:0↙(0:0:01加上59秒的新时间)   

  time:12:0:10↙(11:59:40加上30秒的新时间)

  time:0:49:51↙(23:59:40加上3011秒的新时间)
#include<iostream>
using namespace std;
class time{
    public:
        int hour,minute,second;
        time(int h=0,int m=0,int s=0)
        {
            hour=h;
            minute=m;
            second=s;
        }
        set(int a,int b,int c)
        {
            hour=a;
            minute=b;
            second=c;
        }
}; 
time operator+(time &t,int add)
{
    t.second+=add;
    if(t.second>=60)
    {
        t.minute+=t.second/60;
        t.second%=60;
    }
    if(t.minute>=60)
    {
        t.hour+=t.minute/60;
        t.minute%=60;
    }
    if(t.hour>=24)
    t.hour%=24;
    return t;
}
int main()
{
    int add=0,h,m,s;
    cin>>h>>m>>s>>add;
    while(!(h==0&&m==0&&s==0))
    {
        time t1(h,m,s);
        time t2;
        t2=t1+add;
        cout<<"time:"<<t2.hour<<":"<<t2.minute<<":"<<t2.second<<endl;
        cin>>h>>m>>s>>add;
    }
    return 0;
}
//pta测试显示编译错误：
/*a.cpp:13:1: error: ‘time’ does not name a type
 time operator+(time &t,int add)
 ^~~~
a.cpp: In function ‘int main()’:
a.cpp:36:8: error: expected ‘;’ before ‘t1’
   time t1(h,m,s);
        ^~
a.cpp:36:17: warning: statement is a reference, not call, to function ‘time’ [-Waddress]
   time t1(h,m,s);
                 ^
a.cpp:36:17: warning: statement has no effect [-Wunused-value]
a.cpp:37:8: error: expected ‘;’ before ‘t2’
   time t2;
        ^~
a.cpp:37:10: warning: statement is a reference, not call, to function ‘time’ [-Waddress]
   time t2;
          ^
a.cpp:37:10: warning: statement has no effect [-Wunused-value]
a.cpp:38:3: error: ‘t2’ was not declared in this scope
   t2=t1+add;
   ^~
a.cpp:38:3: note: suggested alternative: ‘tm’
   t2=t1+add;
   ^~
   tm
a.cpp:38:6: error: ‘t1’ was not declared in this scope
   t2=t1+add;
      ^~
a.cpp:38:6: note: suggested alternative: ‘tm’
   t2=t1+add;
      ^~
      tm */