Dale Roberts, Lecturer

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Department of Computer and Information
Science,School of Science, IUPUI
CSCI 230
Arrays Strings and Parameter Passing

• Dale Roberts, Lecturer
• IUPUI
• droberts_at_cs.iupui.edu

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Character Arrays

• Character arrays
• String is really a static array of characters,
  ex first
• Character arrays can be initialized using string
  literals
• char string1 "first"
• Null character '\0' terminates strings
• string1 actually has 6 elements
• It is equivalent to char string1 'f', 'i',
  'r', 's', 't', '\0'
• Can access individual characters
• string1 3 is character s
• Array name is address of array, so not needed
  for scanf char char string220
• scanf( "s", string2 )
• Can read a string with max of size 19 and a null
  character.
• Reads characters until whitespace (space, tab,
  carriage-return, newline, vertical tab)
  encountered
• Can write beyond end of array, be careful

Null character (indicates string termination)
is NOT used, why?
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Passing Arrays to Functions

• Passing arrays
• To pass an array argument to a function, specify
  the name of the array without any brackets
• int myArray 24
• ...
• myFunction( myArray, 24 )
• ...
• Array size usually passed to function
• Arrays passed call-by-reference
• the called functions can modify the element
  values in the callers original array
• Name of array is the address of first element of
  the array
• Function knows where the array is stored.
  Therefore, when the called function modifies
  array elements in its function body, it is
  modifying the actual elements of array in the
  original memory locations

main()
myArray
myFunction()
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Passing Arrays to Functions (cont.)

• Example include ltstdio.hgt
• main()
• int a10
• printf(a p \n a0 p\n, a, a0)
• output a FFEE
• a0 FFEE
• Passing array elements
• Individual elements of an array are passed by
  call-by-value
• Pass subscripted name (i.e., myArray 3 ) to
  function
• Example compare(a0, a1)
• An array is a vector while individual elements
  are scalars.
• Function prototype
• void modifyArray( int b, int arraySize )
• Parameter names optional in prototype
• int b could be written int

will be passed by value
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• Function definitions
• Pass array to a function
• Pass array element to a function
• Print

Entire arrays passed call-by-reference, and can
be modified
Array elements passed call-by-value, and cannot
be modified
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• Function definitions

Effects of passing entire array call by
reference The values of the original array
are 0 1 2 3 4 The values of the modified
array are 0 2 4 6 8 Effects of passing
array element call by value The value of
a3 is 6 Value in modifyElement is 12 The value
of a3 is 6
Program Output