Compilare: user.c: In function ‘main’: user.c:24:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:28:4: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &x); ^~~~~~~~~~~~~~~~~~~~~ user.c:44:2: warning: ‘end’ may be used uninitialized in this function [-Wmaybe-uninitialized] for (unsigned i = start - 1; i >= end; i--) { ^~~ user.c:44:16: warning: ‘start’ may be used uninitialized in this function [-Wmaybe-uninitialized] for (unsigned i = start - 1; i >= end; i--) { ^