Compilare: user.cpp: In function ‘void build(int, int, int)’: user.cpp:44:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&A[nod].prefix);A[nod].sufix=A[nod].sumatotala=A[nod].sumamaxima=A[nod].prefix;return ; ^ user.cpp: In function ‘int main()’: user.cpp:55:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&N); ^ user.cpp:57:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&M); ^ user.cpp:60:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d",&op,&a,&b); ^