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C99 The C Standard defines octal constants as a 0 followed by octal digits (0 1 2 3 4 5 6 7). This can lead to programming errors Programming errors can occur when decimal values are mistakenly specified as octal constants.

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In this noncompliant code example, a decimal constant is mistakenly prefaced with zeros so that all the constants are a fixed length.:

i_array[0] = 2719;
i_array[1] = 4435;
i_array[2] = 0042;

Although it may appear that that i_array[2] is assigned the decimal value 42, it is actually assigned the decimal value 34.

Compliant

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Solution

To avoid using wrong values and to make the code more readable, don't do not preface constants with zeroes if the value is meant to be decimal.:

i_array[0] = 2719;
i_array[1] = 4435;
i_array[2] =   42;

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Misrepresenting decimal values as octal can lead to incorrect comparisons and assignments.

Related Guidelines

ISO/IEC 9899:1999 Section 6.4.4.1 "Integer constants"

MISRA Section 6.7 Rule 7.1

Bibliography

Automated Detection

Related Guidelines

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