Compilare: main.c: In function 'main': main.c:40:2: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(read,"%d%d",&number_of_vertices,&number_of_arcs); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:48:3: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(read,"%d%d%d",&x,&y,&cost); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~