Compilare: main.cpp: In function 'int main()': main.cpp:19:14: warning: variable 'fo' set but not used [-Wunused-but-set-variable] FILE*fi,*fo; ^~ main.cpp:24:30: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m); ^ main.cpp:25:79: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(int i = 1; i <= m; i++) fscanf(fi,"%d%d%d", &M[i].u, &M[i].v, &M[i].w); ^