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This example only illustrates the side-effect issue. The output differs depending on the character set and one should not make assumptions about the order of the letters. For example, when run on a machine using an ASCII derived code set such as ISO-8859 or Unicode, this code sample will print out the 26 lower case letters of the English alphabet. However, if run with an EBCDIC based code set such as Codepage 037 or Codepage 285, punctuation marks marks or symbols might get printed out in between the letters.
Risk Assessment
Using an expression that has side effects as the stream argument to getc() or putc() can result in unexpected behavior and possibly abnormal program termination.
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