Compilare: user.c: In function ‘main’: user.c:37:35: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] fprintf(f2,"%lld S\n",abs(vol-ss+v[st])); ^ user.c:37:24: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘int’ [-Wformat=] fprintf(f2,"%lld S\n",abs(vol-ss+v[st])); ^ user.c:38:24: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘int’ [-Wformat=] fprintf(f2,"%lld D",abs(vol-ss)); ^ user.c:13:5: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d",&n); ^ user.c:15:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d ",&lic); ^ user.c:28:5: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d",&x); ^