Question: I try to create a program that can evaluate simple math expression like "4+4". The expression is given from the user. 

The program saves it in a `char*` and then searches for binary operation (+,-,\*,:) and does the operation. 

The problem is that I can't figure out how to convert the **single** `char` into a `double` value. 

I know there is the `atof` function but I want to convert single `char`.

There is a way to do that without creating a `char*`?

Answer: 
I use that directive in one of my apps and I can get that button to appear by using the using the `file_browser_callback` function in the options. 

Do you get any errors in the JavaScript console? Perhaps you can make a simple CodePen or JS Fiddle of this so people can see your code?

EDIT: Here is a CodePen that does what you want ... it does get that button to appear. The `file_browser_callback` function just logs something to the browser's console but this shows that you can indeed have that button while using that Angular directive.

<http://codepen.io/michaelfromin/pen/BKOGZG>
This has worked for me, used @tinymce/angular - angular version 11

In component.html file

```
<editor [id]="'editorID1'" style="margin-left: 0em" [formControlName]="'questiontext'" placeholder="Date"
       class="form-control" apiKey=" place your api key here" [init]="editorConfig">
</editor>

```

It's in ts file:

```
  let editorConfig = {
  paste_data_images: true,

  file_picker_callback: function(callback:any, value:any, meta:any) {
    var input = document.createElement('input');
    input.setAttribute('type', 'file');
    input.setAttribute('accept', 'image/*');
      if (meta.filetype == 'image') {
         input.click();
         // jQuery('#test-upload').trigger('click');
         //   input.on('change', function(e:any) {               
          input.onchange = function (e:any) {
          //jQuery('#test-upload').on('change', function(e:any) {
              var file:any = e.target.files[0];
              var reader = new FileReader();
              reader.onload = function(e: any) {
                  callback(e.target.result, {
                      alt: ''
                  });
              };
              reader.readAsDataURL(file);
          };
      }
  },

...
}

```