Compilare: user.cpp: In function ‘int main()’: user.cpp:25:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &N, &M, &K); ^ user.cpp:30:83: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d", &v[i].j1, &v[i].i1, &v[i].j2, &v[i].i2, &v[i].val); ^ user.cpp: At global scope: user.cpp:16:20: warning: ‘u’ defined but not used [-Wunused-variable] struct {int x, y;} u[DIM][DIM]; ^