Pangram checker

You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.

For example:   The quick brown fox jumps over the lazy dog.



Task

Write a function or method to check a sentence to see if it is a   pangram   (or not)   and show its use.



Related tasks

   determine if a string has all the same characters
   determine if a string has all unique characters


 
#!/bin/ksh
 
# Pangram checker
 
#	# Variables:
#
alphabet='abcdefghijklmnopqrstuvwxyz'
 
typeset -a strs
strs+=( 'Mr. Jock, TV quiz PhD., bags few lynx.' )
strs+=( 'A very mad quack might jinx zippy fowls.' )
 
#	# Functions:
#
 
#	# Function _ispangram(str) - return 0 if str is a pangram
#
function _ispangram {
	typeset _str ; typeset -l _str="$1"
	typeset _buff ; _buff="${alphabet}"
	typeset _i ; typeset -si _i
 
	for ((_i=0; _i<${#_str} && ${#_buff}>0; _i++)); do
		_buff=${_buff/${_str:${_i}:1}/}
	done
	return ${#_buff}
}
 
 ######
# main #
 ######
 
typeset -si i
for ((i=0; i<${#strs[*]}; i++)); do
	_ispangram "${strs[i]}"
	if (( ! $? )); then
		print "${strs[i]}   <<< IS A PANGRAM."
	else
		print "${strs[i]} <<< Is not a pangram."
	fi
done
 