How to pass variables from one function to another or combine functions

There are 2 ways that would be the most simple.

1. Do it with a function call.

2. Make the variables global.

The first would be done like so:

function my_func() {
    $styles="stuff";

    second_func($styles);
}

function second_func($styles) {
    // do something with $styles
    var_dump($styles);
}

The second way would be done like so:

// Set global variable
$GLOBALS['styles'] = 'stuff';


// Call it anywhere else
global $styles;

For more on globals:
http://php.net/manual/en/language.variables.scope.php

EDIT: See below.

global $styles;

$styles = array(
  array(
    'slug'=>'body_bcolor', 
    'default' => "#F1F2F1",
    'label' => __('Body Background Color', 'impressive'),
    'css_class' => 'body',
    'attribute' => 'background-color:',
    'section' => 'body',
    'type' => 'color'
  ),
  array(
  'slug'=>'max_container_width', 
  'default' => '1440',
  'label' => __('Maximal Container Width', 'impressive'),
  'css_class' => '.header',
  'attribute' => 'max-width:',
  'section' => 'body',
  'type' => 'number'
  )
);


function im_customize_register( $wp_customize ) {
global $styles;
//Custom Sections

$wp_customize->add_section(
    'body',
    array(
        'title'     => __('Body Settings', 'impressive'),
        'priority'  => 200
    )
);

foreach( $GLOBALS['styles'] as $style ) {

  $wp_customize->add_setting(
    $style['slug'], array(
      'default' => $style['default'],
      'type' => 'option', 
      'capability' => 
      'edit_theme_options'
    )
  );

 if ( $style['type'] == 'color' ) {
  $wp_customize->add_control(
    new WP_Customize_Color_Control(
      $wp_customize,
      $style['slug'], 
      array('label' => $style['label'],
      'section' => $style['section'],
      'settings' => $style['slug'],
      'type' => $style['type'])
    )
  );
  } elseif ( $style['type'] == 'image' && $style['section'] == 'header_image' ) {
    $wp_customize->add_control(
        new WP_Customize_Header_Image_Control(
        $wp_customize,
        $style['slug'], 
        array('section' => $style['section'],
        'settings' => $style['slug'])
    )
  );
 } else {
  $wp_customize->add_control(
    new WP_Customize_Control(
      $wp_customize,
      $style['slug'], 
      array('label' => $style['label'],
      'section' => $style['section'],
      'settings' => $style['slug'],
      'type' => $style['type'])
    )
  );

  }

}

}
add_action( 'customize_register', 'im_customize_register' );


function im_custom_style_create() {
global $styles;

wp_enqueue_style( 'im_custom_style', get_template_directory_uri() . '/css/im_custom_style.css' );

foreach( $styles as $style ) {

if ( $style['attribute'] == $max_width ) { $measurement_unit="px"; }

if ( get_option( $style['slug'] ) == true ) { $custom_css="" . $style['css_class'] . ' { ' . $style['attribute'] . ' ' . get_option( $style['slug'] ) . $measurement_unit . '; } '; };

wp_add_inline_style ('im_custom_style', $custom_css);
}

}
add_action( 'wp_enqueue_scripts', 'im_custom_style_create' );