memory - C++: Uninitialized variables garbage

Question

int myInt;
cout << myInt; // Garbage like 429948, etc

If I output and/or work with uninitialized variables in C++, what are their assumed values?

• Actual values in the memory from the "last user"?

e.g.: Program A is closed, it had an int with the value 1234 at 0x1234 -> I run my program, myInt gets the address 0x1234, I output it like above -> 1234

• Is it just random garbage?

Answer 1

"Random garbage" but with emphasis on "garbage", not on "random" – i.e., absolutely arbitrary garbage without even any guarantee of "randomness" – the compiler and runtime systems are allowed to have absolutely anything there (some systems may always give zeros, other might give arbitrary different values, etc., etc.).