Compilare: main.cpp: In function 'int main()': main.cpp:60:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(poz < s.size()) ~~~~^~~~~~~~~~ main.cpp:76:17: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if(signs.empty() || order(signs.top(), s[poz])) ^~ main.cpp:78:21: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' continue; ^~~~~~~~ main.cpp: In function 'int calc(int, int, char)': main.cpp:29:1: warning: control reaches end of non-void function [-Wreturn-type] } ^