Compilare: user.cpp: In function ‘int eval(int)’: user.cpp:61:51: warning: operation on ‘nr’ may be undefined [-Wsequence-point] if (sir[p] == '(') p++, v[++nr] = eval(nr); ^ user.cpp:62:56: warning: operation on ‘nr’ may be undefined [-Wsequence-point] else if (sir[p] == '[') p++, v[++nr] = eval(nr); ^ user.cpp: In function ‘int main()’: user.cpp:70:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.in","r",stdin); ^ user.cpp:71:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("expresie2.out","w",stdout); ^ user.cpp:73:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(sir + 1); n = strlen(sir + 1); ^ /tmp/cc5pgGme.o: In function `main': user.cpp:(.text.startup+0x53): warning: the `gets' function is dangerous and should not be used.