FAQ: Variables: Lesson - Review

This community-built FAQ covers the “Review” exercise from the lesson “Variables: Lesson”.

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This exercise can be found in the following Codecademy content:

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Hello,
On the final page of the Variables lesson, if you run the code as is without any changes it outputs the value of variableInt as 32764. Can you explain why this happens please?

Depending on the programming language, uninitialized variables may be assigned default values OR they may contain some garbage value OR your program may crash OR your output may keep changing randomly.

In C, using a variable before it is used can cause undefined behavior. Have a look at:

Static and global variables are assigned default values, but for uninitialized automatic variables:

In C and C++, local variables aren’t initialized by default. Uninitialized variables can contain any value, and their use leads to undefined behavior. (Source)

If you copy-paste the original code from the exercise, and run it in different free online c compilers, you will see different results. Some will show 0, some will show a value similar to 32764.

Very cool. Thank you for explaining.

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