All Questions

Yesterday I wrote by mistake #include "iostream"and I haven't realized it because the compiler didn't give an error. Later I realized and I was surprised.

I have tried with this small program :

// Fichero a.h
#ifndef A_H
#define A_H
#endif // A_H

// Fichero a.cpp
#include <iostream>
#include "a.h"
int main(void) {
    std::cout << "Hola Mundo" << std::endl;
    return 0;
}

Which works as expected.
It also works if I put the two includes with double quotes " ", this has surprised me.
If I put the two includes with minor major < >it gives me a compilation error, which is what I expect:

a.cpp:2:15: fatal error: ah: No such file or directory

I thought that :

• #include < >it is for system headers or libraries.
• #include " "it is for programmer headers.

But clearly not because iostream can also be included with " ".
Can I just include it all with " "?
Or could it have some adverse effect doing everything with " "? And if so, what criteria to use to decide whether each include is done with " "or < >?

I would like to know how I can prevent the control from EditTextdisplaying the keyboard every time it receives focus or the user hovers over the control.

The reason for this is that I want to use said control to show a calendar dialog every time it receives the focus or the user hovers over the control, so that the control will get the value of the date (I already have this last part implemented ).

In principle, according to the Android documentationandroid:inputType="none" , setting the field's type attribute EditTextmakes the text non-editable, so the expected behavior is that the android keyboard is not displayed . However, the keyboard still appears each time the control receives focus or the user clicks on the control.

Here is the xml code to define the control:

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="16dp"
    android:paddingRight="16dp">

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <!-- Controles --> 

        <android.support.design.widget.TextInputLayout
            android:id="@+id/tiFechaCaducidad"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/etFechaCaducidad"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/fechacaducidad"
                android:singleLine="true"
                android:inputType="none"
                android:drawableRight="@drawable/ic_arrow_drop_down" />
        </android.support.design.widget.TextInputLayout>

    </android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

I am working on a project and I use git for version management. The problem I have is that if I change the permissions of the directory, they appear to me that the files were modified, but when I use git diffto observe the changes, a list like the following appears:

diff --git a/assets/images/icon-32-bcache.png b/assets/images/icon-32-bcache.png
old mode 100644
new mode 100755
diff --git a/assets/images/icon-32-help.png b/assets/images/icon-32-help.png
old mode 100644
new mode 100755

I consider these changes garbage to be in a commit. Is there a command that ignores these changes?

I have the following Arrayfrom a selectcontaining the IDs of a table:

var arreglo = ["1", "2", "4", "5"]

I want to know if it "3"is contained in arreglo. In Python it is possible to do this:

>>> arreglo = ['1', '2', '4', '5']
>>> '3' in arreglo
False

But trying this from the console in JavaScript to the surprise that it doesn't work the same way:

> var arreglo = ["1", "2", "4", "5"]
> "3" in arreglo
true

Doing some research on the MDN documentation I found the problem (emphasis mine):

The operator inreturns true if the specified property is found on the specified object.

Indeed, arregloit has the property (or index) "3", that is why it returns me true:

> Object.keys(arreglo)
["0", "1", "2", "3"]

My query, how can I do then to validate that an object is contained within an array?

Let's say I have a file archivowith many lines, but I only want to print one particular line, say number n.

How can I achieve this using tools that are on a standard Linux system? The option head XX archivo | tail -Nseems impractical to me.