for循环不起作用？ [英] The for loop does not work?

问题描述

  #include   <   iostream  >  
   #include   <   iomanip  < span class =code-keyword>>  
   #include   < span class =code-string>  C1A7E1_MyTime.h 
  使用 命名空间标准; 
 
 MyTime * DetermineElapsedTime（ const  MyTime * tp1， const  MyTime * tp2） ; 
  int  main（）
 {
  for （ int  loop_count =  0 ; loop_count<  3 ; loop_count ++ ）
 {
 
 cout<<  输入时间点1，空格分隔：\ n; 
 cin>> tm1.hours>> tm1.minutes>> tm1.seconds; 
 cout<<  输入时间点1，空格分隔：\ n; 
 cin>> tm2.hours>> tm2.minutes>> tm2.seconds; 
 cout<<  输入功能！; 
 DetermineElapsedTime（ const  tm1， const  tm2）
} 
 < span class =code-keyword> const  MyTime tm1 = { 2 ， 0 ，  0 }; 
  const  MyTime tm2 = { 0 ， 0 ， 0 }; 
 MyTime time_dif = * DetermineElapsedTime（& tm1，& tm2）; 
 cout<<  从;经过的时间
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm1.hours<<  ：; 
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm1.minutes<<  ：; 
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm1.seconds; 
 cout<<   to; 
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm2.hours<<  ：; 
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm2.minutes<<  ：; 
 cout<< setfill（'  0'）<< setw（ 2 ）<< tm2.seconds; 
 cout<<  是; 
 cout<< time_dif.hours<<  ：<< time_dif.minutes<<  ：<< time_dif.seconds<<   \ n; 
} 
 
 
 C1A7E1_MyTime.h 
 
 
  #ifndef Class_Test_C1A7E1_MyTime_h 
   #define Class_Test_C1A7E1_MyTime_h 
  使用 命名空间标准; 
  struct  MyTime { int 小时，分钟，秒; };  / *  请勿更改此* /  
 
 ＃endif 
  
 C1A7E1_DetermineElapsedTime.cpp 
 
 
  #include  < span class =code-preprocessor> <   iostream   >  
   #include      C1A7E1_MyTime.h 
  使用 命名空间标准; 
 MyTime * DetermineElapsedTime（ const  MyTime * tp1， const  MyTime * tp2）
 {
  static  MyTime return_time; 
 MyTime testy1，testy2; 
 testy1 = * tp1; 
 testy2 = * tp2; 
  long  time_point_dif; 
 time_point_dif =（ long （testy1.hours）*  3600  +  long （testy1.minutes）*  60  +  long （testy1.seconds ）） -  \ 
（ long （testy2.hours）*  3600  +  long （testy2.minutes）*  60  +  long （ testy2.seconds））; 
 return_time.hours =  int （time_point_dif /  3600 ）; 
 time_point_dif  -  = return_time.hours *  3600 ; 
 return_time.minutes =  int （time_point_dif /  60 ）; 
 time_point_dif  -  = return_time.minutes *  60 ; 
 return_time.seconds =  int （time_point_dif）; 
  return （& return_time）; 
 
} 

我的尝试：



我试图创建数据类型int tm1，tm2？不知道为什么我收到的错误不在范围内。

解决方案

 const MyTime tm1 = {2,0,0}; 
 const MyTime tm2 = {0,0,0}; 
 

在for循环块之后声明。移到for循环之前再试一次。

引用：

我试图创建数据类型int tm1，tm2？不知道为什么我收到的错误不在范围内。

编译器不满意，因为你在创建它们之前使用 tm1 和 tm2 。

原则上，在声明之前你不能使用它。



[更新]

< blockquote class =quote>

引用：

是的，但是我该怎么办呢？我试图在手前声明变量但它仍然不起作用？

Don不要将它们声明为 const 或不要写入它们。

#include <iostream>
#include <iomanip>
#include "C1A7E1_MyTime.h"
using namespace std;

MyTime *DetermineElapsedTime(const MyTime *tp1, const MyTime *tp2);
int main()
{
   for (int loop_count = 0; loop_count < 3; loop_count++)
    {
    	
        cout << "Enter time point one, space separated:\n";
        cin >> tm1.hours >> tm1.minutes >> tm1.seconds;
        cout << "Enter time point one, space separated:\n";
        cin >> tm2.hours >> tm2.minutes >> tm2.seconds;
        cout << "entering function!";
        DetermineElapsedTime(const tm1, const tm2)
				 }
    const MyTime tm1 = { 2, 0, 0};
    const MyTime tm2 = { 0, 0, 0};
    MyTime time_dif = *DetermineElapsedTime(&tm1, &tm2);
    cout << "The time elapsed from ";
    cout << setfill('0') << setw(2) << tm1.hours << ":";
    cout << setfill('0') << setw(2) << tm1.minutes << ":";
    cout << setfill('0') << setw(2) << tm1.seconds;
    cout << " to ";
    cout << setfill('0') << setw(2) << tm2.hours << ":";
    cout << setfill('0') << setw(2) << tm2.minutes << ":";
    cout << setfill('0') << setw(2) << tm2.seconds;
    cout << " is ";
    cout << time_dif.hours << ":" << time_dif.minutes << ":" << time_dif.seconds << "\n";
}


C1A7E1_MyTime.h


#ifndef Class_Test_C1A7E1_MyTime_h
#define Class_Test_C1A7E1_MyTime_h
using namespace std;
struct MyTime { int hours, minutes, seconds; }; /* do not change this */

#endif

C1A7E1_DetermineElapsedTime.cpp


#include <iostream>
#include "C1A7E1_MyTime.h"
using namespace std;
MyTime *DetermineElapsedTime(const MyTime *tp1, const MyTime *tp2)
{
    static MyTime return_time;
    MyTime testy1, testy2;
    testy1 = *tp1;
    testy2 = *tp2;
    long time_point_dif;
    time_point_dif = (long(testy1.hours) * 3600 + long(testy1.minutes) * 60 + long(testy1.seconds)) - \
    (long(testy2.hours) * 3600 + long(testy2.minutes) * 60 + long(testy2.seconds));
    return_time.hours = int(time_point_dif / 3600);
    time_point_dif -= return_time.hours * 3600;
    return_time.minutes = int(time_point_dif / 60);
    time_point_dif -= return_time.minutes * 60;
    return_time.seconds = int(time_point_dif);
    return(&return_time);
  
}

What I have tried:

I tried to create data type int tm1, tm2? Not sure why I am getting an error not in scope.

解决方案

const MyTime tm1 = { 2, 0, 0};
const MyTime tm2 = { 0, 0, 0};

are declared after the for loop block. Move to before the for loop and try again.

Quote:

I tried to create data type int tm1, tm2? Not sure why I am getting an error not in scope.

The compiler is unhappy because you use tm1 and tm2 before creating them.
By principle, you can't use something before declaring it.

[Update]

Quote:

Yes but what do I do about it I have tried to declare the variable before hand and it still does not work?

Don't declare them as const or don't write into them.

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