Variables of built-in types should be initialized before you first use them, but there are some situations when the compiler will provide a default value.
If you declare a variable at file scope, or globally in your project, and you do not give it an initial value, the compiler will give it a default value. For example:
int outside; int main() { outside++; cout << outside << endl; }
This code will compile and run, printing a value of 1; the compiler has initialized outside to 0, which is then incremented to 1. The following code will not compile:
int main() { int inside; inside++; cout << inside << endl; }
The compiler will complain that the increment operator is being used on an uninitialized variable.
In the ...
