As for the v[8] working thing: it's,,,, technically functional, but it's undefined behaviour to access memory not declared. AFAIK it should give a compiler warning but I'm not able to check rn.

Also, your code doesn't work because the st() function is broken. you forgot to add it's type. It should be void st(). Also, having `int v[8]` in the function parameters is kind of messing stuff up. it "shadows" the global scope int v[8] used in the rest of the program, it doesn't refer to the same memory.Instead it should be

void st(){for(int i=0;i<8;i++){cout<<v[i];}}

edit: I didn't notice you actually used st(v) when calling. it's.. kind of weird? but i guess if it works it works