Compilare: user.cpp: In function ‘void back(int)’: user.cpp:21:38: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(j1<=st[k-1][2]&&j>j2||(j>j1&&st[k-1][2]>=j2&&i==st[k-1][1])) ^ user.cpp:18:25: warning: unused variable ‘i1’ [-Wunused-variable] int i1,j1,i2,j2; ^ user.cpp:18:31: warning: unused variable ‘i2’ [-Wunused-variable] int i1,j1,i2,j2; ^ user.cpp: In function ‘int main()’: user.cpp:31:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bilete.in","r",stdin); ^ user.cpp:32:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bilete.out","w",stdout); ^ user.cpp:33:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&q); ^