Given the state of the stack and registers, can we predict the outcome of printf’s undefined behavior

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You try to use %d for float:

d specifier is used for signed decimal integer

f specifier is used for decimal floating point

Using wrong specifier leads to Undefined behavior

You relied on address of an automatic variable:

I try to predict the output by viewing the memory near a

a is an automatic variable, its address changes every time you compile the code, so memory-near-a also changes every time you compile the code.

So, “viewing the memory near a” also causes Undefined behavior.

Solution:

You have nothing to do with Undefined behavior (in this case), so just forget it for saving time, it will make your life easier.

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