Compilare: user.cpp: In function ‘bool cmp(Line, Line)’: user.cpp:7:57: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] bool cmp(Line A, Line B){return A.a > B.a || A.a == B.a && A.b > B.b;} ~~~~~~~~~~~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:23:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m); ^ user.cpp:24:82: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i = 1; i <= n; i++) fscanf(fi,"%d%d", &v[i].a, &v[i].b), v[i].ind = i; ^ user.cpp:30:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d", &x); ^