Compilare: user.cpp: In function ‘int eval(int, int)’: user.cpp:12:48: warning: NULL used in arithmetic [-Wpointer-arith] if(s[i][i1] == '\n' || s[i][i1] == NULL) break; ^ user.cpp:13:48: warning: NULL used in arithmetic [-Wpointer-arith] if(s[j][j1] == '\n' || s[j][j1] == NULL) continue ; ^ user.cpp: In function ‘int main()’: user.cpp:29:8: warning: unused variable ‘aux’ [-Wunused-variable] int aux = 0, mex = 0; ^ user.cpp:22:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("randuri.in", "r", stdin); ^ user.cpp:23:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("randuri.out", "w", stdout); ^