SEI CERT C Coding Standard

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Code Block
bgColor#ffcccc
double a = 3.0,;
double b = 7.0, c;
double c = a / b;

if (c == a / b) {
  printf ("comparisonComparison succeeds\n");
} else {
  printf ("unexpectedUnexpected result\n");
}

On a test IA-32 Linux machine with GCC Compiler Version 3.4.4 this code prints:

Code Block
unexpectedUnexpected result

But when it is compiled with the -O option this code prints:

Code Block
comparisonComparison succeeds

Risk Analysis

Failing to understand the limitations of floating point numbers can result in unexpected mathematical results and exceptional conditions, possibly resulting in a violation of data integrity.

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