简单的C ++问题 - C ++ 101 [英] Simple C++ problem - C++ 101

问题描述

大家好，


我在所罗门群岛辅导计算机科学入门和

我们使用C ++作为首选语言（很好）。请注意，我不是一个C ++程序员，但是我已经在大多数

主流语言编程了20年。我们正在学习如何使用
代码，而不仅仅是C ++。课堂上的家伙们在几天内完成了他们的最终任务

，我们有一个简单的问题需要克服。

问题是这样的：


程序读入一个整数数组，指示一个方向进入的机器人

方向，在20 x 20网格中。前两个整数（从文件中读取
）是机器人的起始位置，并且必须在函数中验证为
作为20中的有效位置x 20 grid。

起始位置是文件中的全局变量。布尔值

''有效''作为全局声明为false。要验证的代码是

，如下所示：


void check_valid（）

{

if （（start_x> = 0 || start_x< = 20）&&（start_y> = 0 || start_y< =

20））//你知道我的意思吗？ br />
{

有效=真;

}

}


问题是，如果初始start_x和start_y位置有效，那么''if''逻辑永远不会有效。任何回复都有一个很大的谢谢。

这些家伙试图在他们的课程中取得进展

Solomons的极大不确定性（只需进行谷歌搜索和找出

关于我们过去几周遇到的麻烦。）


尼克

解决方案

ni * ***************@hotmail.com 写道：

大家好，

我在辅导计算机科学入门在所罗门群岛和我们使用C ++作为首选语言（很好）。请注意，我不是一个C ++程序员，但是我已经用大多数主流语言编写了20年以上的程序。我们正在学习如何编写代码，而不仅仅是C ++。班上的家伙们在几天内完成了他们的最终任务，我们有一个简单的问题需要克服。这个问题是这样的：

程序读入一个整数数组，用20×20网格指示一个进入方向的机器人。前两个整数（从文件读入
）是机器人的起始位置，必须在函数中验证为20 x 20网格内的有效位置。
起始位置是文件中的全局变量。布尔值
''valid''也被声明为false为全局。要验证的代码如下：

void check_valid（）
{
if（（start_x> = 0 || start_x< = 20）& ;&（start_y> = 0 || start_y< =
20））//你知道我的意思
{
有效=真;
} }

问题是，如果初始start_x和start_y位置有效，则if逻辑永远不会起作用。任何回复都会有一个很大的谢谢。这些人试图在Solomons中有很大的不确定性（只做Google搜索并找出关于过去几周我们经历过的麻烦。

尼克

i像这样运行你的代码


//main.cpp

#include< iostream>


使用命名空间std;


bool valid = false;

int start_x = 2;

int start_y = 3;


int main（）

{

if（（start_x> = 0 || start_x< = 20）&&（start_y> = 0 || start_y< = < br $>
20））

{

有效=真;

cout<<" hello"<< ; endl;

}

返回0;

}


//输出
你好


出了什么问题！

ni **************** @ hotmail.com 写道：

void check_valid（）
{
if（（start_x> = 0 || start_x< = 20）&& （start_y> = 0 || start_y< =
20））//你知道我的意思
{
有效=真;
}
} <问题是，如果初始start_x和start_y位置有效，则if逻辑永远不会起作用。任何回复都会有一个很大的谢谢。这些人试图在Solomons中有很大的不确定性（只做Google搜索并找出关于我们在过去几周里经历过的麻烦。）

相反，无论start_x和
$的值如何，有效都设置为true b $ b start_y因为任何数字都是大于0 *或*小于20，你

可能意味着：

if（（start_x> = 0& ;& start_x< = 20）&&（start_y> = 0&& start_y< =

20））

valid = true;


如果start_x和start_y都在

范围内，这将设置为true [0,20]


Abdo Haji-Ali

程序员

In | Framez

Abdo Haji-Ali写道：

ni ** ************** @ hotmail.com 写道：

void check_valid（）
if（
start_x> = 0 || start_x< = 20）&& （start_y> = 0 || start_y< =
20））//你知道我的意思
{
有效=真;
}
} <问题是，如果初始start_x和start_y位置有效，则if逻辑永远不会起作用。任何回复都会有一个很大的谢谢。这些人试图在Solomons中有很大的不确定性（只做Google搜索并找出关于过去几周我们经历过的麻烦。）

相反，无论start_x和
start_y的值是多少都设置为true，因为任何数字都是大于0 *或*小于20，你可能意味着：
if（（start_x> = 0&& start_x< = 20）&&（start_y> ; = 0&& start_y< =
20））
有效=真;

如果start_x和start_y都在 range [0,20]

如果网格的大小为

，忘记提一下你可能需要[0,19]的范围20 ...

Abdo Haji-Ali

程序员

In | Framez

Hi all,

I am tutoring introductory computer science in the Solomon Islands and
we are using C++ as the language of choice (nice). Please note that I
am no way a C++ programmer, but have but I have programmed in most
mainstream languages over the paste 20 years. We are learning HOW to
code, not just C++. The dudes in the class have their final assignment
in a couple of days and we have a simple problem to overcome. The
problem is this:

The program reads in an array of integers which instructs a robot which
direction to go in, in a 20 x 20 grid. The first two integers (read in
from a file) are the starting position of the robot, and have to be
validated in a function as a valid position within the 20 x 20 grid.
The starting postions are global variables in the file. The boolean
''valid'' is declared as false also as a global. The code to validate is
as follows:

void check_valid( )
{
if ((start_x >= 0 || start_x <= 20) && (start_y >= 0 || start_y <=
20)) // you know what I mean
{
valid = true;
}
}

The problem is that if the initial start_x and start_y positions ARE
valid, the ''if'' logic never work. Any replies come with a big Thanks In
Advance for these guys trying to get through their course in a time of
great uncertainty in the Solomons (just do a Google search and find out
about the troubles we''ve been through in the last few weeks).

Nick

解决方案

ni****************@hotmail.com wrote:

Hi all,

I am tutoring introductory computer science in the Solomon Islands and
we are using C++ as the language of choice (nice). Please note that I
am no way a C++ programmer, but have but I have programmed in most
mainstream languages over the paste 20 years. We are learning HOW to
code, not just C++. The dudes in the class have their final assignment
in a couple of days and we have a simple problem to overcome. The
problem is this:

The program reads in an array of integers which instructs a robot which
direction to go in, in a 20 x 20 grid. The first two integers (read in
from a file) are the starting position of the robot, and have to be
validated in a function as a valid position within the 20 x 20 grid.
The starting postions are global variables in the file. The boolean
''valid'' is declared as false also as a global. The code to validate is
as follows:

void check_valid( )
{
if ((start_x >= 0 || start_x <= 20) && (start_y >= 0 || start_y <=
20)) // you know what I mean
{
valid = true;
}
}

The problem is that if the initial start_x and start_y positions ARE
valid, the ''if'' logic never work. Any replies come with a big Thanks In
Advance for these guys trying to get through their course in a time of
great uncertainty in the Solomons (just do a Google search and find out
about the troubles we''ve been through in the last few weeks).

Nick

i run your code like this

//main.cpp
#include <iostream>

using namespace std;

bool valid = false;
int start_x = 2;
int start_y = 3;

int main()
{
if ((start_x >= 0 || start_x <= 20) && (start_y >= 0 || start_y <=
20))
{
valid = true;
cout<<"hello"<<endl;
}
return 0;
}

//output
hello

what`s wrong!

ni****************@hotmail.com wrote:

void check_valid( )
{
if ((start_x >= 0 || start_x <= 20) && (start_y >= 0 || start_y <=
20)) // you know what I mean
{
valid = true;
}
}

The problem is that if the initial start_x and start_y positions ARE
valid, the ''if'' logic never work. Any replies come with a big Thanks In
Advance for these guys trying to get through their course in a time of
great uncertainty in the Solomons (just do a Google search and find out
about the troubles we''ve been through in the last few weeks).

On the contrary, valid is set to true whatever the value of start_x and
start_y because any number is "bigger than 0 *or* less than 20", you
probably meant:
if ((start_x >= 0 && start_x <= 20) && (start_y >= 0 && start_y <=
20))
valid = true;

This would set valid to true if both start_x and start_y are in the
range [0,20]

Abdo Haji-Ali
Programmer
In|Framez

Abdo Haji-Ali wrote:

ni****************@hotmail.com wrote:

void check_valid( )
{
if ((start_x >= 0 || start_x <= 20) && (start_y >= 0 || start_y <=
20)) // you know what I mean
{
valid = true;
}
}

The problem is that if the initial start_x and start_y positions ARE
valid, the ''if'' logic never work. Any replies come with a big Thanks In
Advance for these guys trying to get through their course in a time of
great uncertainty in the Solomons (just do a Google search and find out
about the troubles we''ve been through in the last few weeks).

On the contrary, valid is set to true whatever the value of start_x and
start_y because any number is "bigger than 0 *or* less than 20", you
probably meant:
if ((start_x >= 0 && start_x <= 20) && (start_y >= 0 && start_y <=
20))
valid = true;

This would set valid to true if both start_x and start_y are in the
range [0,20]

Forgot to mention that you probably need a range of [0,19] if the size
of the grid is 20...

Abdo Haji-Ali
Programmer
In|Framez

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