Is the point that any var declared in between the braces automatically goes out of scope, to minimize potential duplication of var names and unintended behavior

Is the point that any var declared in between the braces automatically goes out of scope, to minimize potential duplication of var names and unintended behavior ? The worst I've seen is old school C programmers who insisted on reusing loop variables in other loops. Even worse, those loop variables were declared inside the loop declaration, which old C standards allowed to visible outside of it. So they would have stuff like this for(int i=0; i<10; i++) { ... } for (;i<20;i++) { ... } Later versions of C++ disallowed this, which led to some interesting compile failures, which led to insistence of the old stubborn programmers that new compilers simply not be used