Get warning when a variable is shadowed

by

Both gcc and clang support the -Wshadow flag which will warn about variables that shadow one another. For example the warning I receive from gcc for your code is the following:

warning: declaration of ‘n’ shadows a previous local [-Wshadow]
for (int n = 1; n <= 10; n++){
         ^
warning: shadowed declaration is here [-Wshadow]
int n = 3;
    ^

gcc documents the flag here and says:

Warn whenever a local variable or type declaration shadows another
variable, parameter, type, class member (in C++), or instance variable
(in Objective-C) or whenever a built-in function is shadowed. Note
that in C++, the compiler warns if a local variable shadows an
explicit typedef, but not if it shadows a struct/class/enum.

In Visual Studio this looks like it was not possible before but seems to be fixed in recent versions.

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