Compilare: main.c: In function 'buildSparseTable': main.c:11:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &lookup[i][0]); ^~~~~~~~~~~~~~~~~~~~~~~~~~ main.c: In function 'main': main.c:37:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("saracsaurege.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:38:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("saracsaurege.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:42:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~ main.c:47:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &l, &r); ^~~~~~~~~~~~~~~~~~~~~