Compilare: user.cpp: In function ‘int expr(int)’: user.cpp:38:49: warning: for increment expression has no effect [-Wunused-value] for(x=expr(lev+1);strchr(leve[lev],*p);x==y) ^ user.cpp: In function ‘int oper(int, int, char)’: user.cpp:19:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int expr(int)’: user.cpp:42:12: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] return x; ^