Compilare: main.cpp: In function 'void StPush()': main.cpp:36:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st[3].size() < cnt / 2) { ~~~~~~~~~~~~~^~~~~~~~~ main.cpp: In function 'void StPop()': main.cpp:51:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st[3].size() > cnt / 2){ ~~~~~~~~~~~~~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:74:19: warning: unused variable 'x' [-Wunused-variable] for (int i = 1, x = 0; i <= n; i++) { ^