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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.

Noncompliant

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Code Example

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;

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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;

Risk Assessment

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

References

\[[ISO/IEC 9899:1999|cplusplus:AA. C References#ISO/IEC 9899-1999]\] Section 6.4.4.1  "Integer constants"
\[MISRA 04\] Section 6.7 Rule 7.1 

Automated Detection

Related Guidelines

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Image Added Image Added Image AddedImage Removed      02. Declarations and Initialization (DCL)      DCL19-C. Use as minimal a scope as possible for all variables and functions