Compilare: user.cpp: In function ‘int main()’: user.cpp:21:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (nr>=0 && s[i]>st[nr] && k>0) {nr--; k--;} ^ user.cpp:22:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] st[++nr] = (char) s[i]; ^ user.cpp:12:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&n,&m); ^ user.cpp:13:21: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",s); ^