human
Double the first element and move zero to end | shift all zero to left side of an array.
Maintain last index with positive value.
If Element is non - zero.
swap current index , with lastSeen non - zero.
next element will be last seen non - zero"
Solution in Python:

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Give me a code to double the first element and move zero to end and the other steps required?
assistant
#Here is code to double the first element and move zero to end and the other steps required.
 def shiftAllZeroToLeft ( arr , n ) :
	lastSeenNonZero = 0
	for index in range ( 0 , n ) :
		if ( array [ index ] != 0 ) :
			array [ index ] , array [ lastSeenNonZero ] = array [ lastSeenNonZero ] , array [ index ]
			lastSeenNonZero += 1