Compilare: main.c: In function 'main': main.c:26:40: warning: operation on 'k' may be undefined [-Wsequence-point] getRectangle(i, j, &xl[++k], &xr[k], &yl[k], &yr[k]); ^~~ main.c:26:40: warning: operation on 'k' may be undefined [-Wsequence-point] main.c:26:40: warning: operation on 'k' may be undefined [-Wsequence-point] main.c:19:5: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d\n", &n, &m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:22:13: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", v[i]+j); ^~~~~~~~~~~~~~~~~~~~~~~