Eroare de compilare: user.c: In function ‘main’: user.c:41:22: error: ‘sum’ undeclared (first use in this function) fprintf(f_out,"%d",sum); ^ user.c:41:22: note: each undeclared identifier is reported only once for each function it appears in user.c:23:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f_in,"%d %d",&m,&n); ^ user.c:27:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f_in,"%d",&v[i]); ^ user.c:30:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f_in,"%d",&w[i]); ^