Compilare: user.c: In function ‘main’: user.c:46:9: warning: implicit declaration of function ‘log’ [-Wimplicit-function-declaration] int width = log(y - x + 1); ^ user.c:46:21: warning: incompatible implicit declaration of built-in function ‘log’ [enabled by default] int width = log(y - x + 1); ^ user.c:27:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d\n", &N, &M); ^ user.c:30:15: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &v[i]); ^ user.c:44:15: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &x, &y); ^