Compilare: user.c: In function ‘search_neighbour’: user.c:24:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:64:5: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:66:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &k, &j); ^~~~~~~~~~~~~~~~~~~~~~~~~~~