Compilare: user.c: In function ‘main’: user.c:29:5: warning: implicit declaration of function ‘log2’ [-Wimplicit-function-declaration] b=log2(z+k); ^ user.c:29:7: warning: incompatible implicit declaration of built-in function ‘log2’ [enabled by default] b=log2(z+k); ^ user.c:9:21: warning: variable ‘b’ set but not used [-Wunused-but-set-variable] long long int i,b,s; ^ user.c:14:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &n); ^ user.c:15:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &k); ^ user.c:18:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &c[0]); ^ user.c:19:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &x); ^ user.c:20:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &y); ^ user.c:21:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%lld", &z); ^