# ----------------------------------------

# Listing 1

a="4711"
b="b ist eine kurze Zeichenkette mit Buchstaben"

print("a:")
print(a)
print(a[0])
print(a[1])
print(a[2])
print(a[3])

print("b:")
print(b)
print(b[0])
print(b[2])
print(b[3])

# ----------------------------------------

# Listing 2

def asciiIndexOfChar(character):
  return bytearray(character,"ASCII")[0]
    
print("asciiIndexOfChar :")
print(asciiIndexOfChar(a[0]))
print(asciiIndexOfChar(a[1]))
print(asciiIndexOfChar(a[2]))
print(asciiIndexOfChar(a[3]))

# ----------------------------------------

# Listing 3

def numberValueOfChar(character):
  offsetAsciiZero = 38
  return asciiIndexOfChar(character) - offsetAsciiZero
    
print("numberValueOfChar :")
print(numberValueOfChar(a[0]))
print(numberValueOfChar(a[1]))
print(numberValueOfChar(a[2]))
print(numberValueOfChar(a[3]))

# ----------------------------------------

# Listing 4

def printNumberValues(s):
  index = 0
  length = len(s)
  print("Zeichenkette ", s ," ist ", length, " Zeichen lang")
  while index < length :
    print("index = ", index, "   numberValueOfChar() = ", numberValueOfChar(s[index]))
    index = index + 1
				
printNumberValues(a)

# ----------------------------------------

# Listing 5

def countNumericChars(z):
  index = 0
  length = len(z)
  numberOfNumerics = 0
  while index < length:
    if (asciiIndexOfChar(z[index]) >= 48) and (asciiIndexOfChar(z[index]) <= 57) :
      numberOfNumerics = numberOfNumerics + 1
    index= index + 1
  return numberOfNumerics

f="1234 abcd"
print("f enthlt ", countNumericChars(f), " arabische Ziffern")

# ----------------------------------------

# Listing 6

z="1231"
print("Zahl in Form einer ASCII-Zeichenkette: ", z) 
print("Quersumme davon: ", digitSum(z))

# ----------------------------------------