Compilare: user.cpp: In function ‘int main()’: user.cpp:19:39: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d%d%d" ,&n,&m,&l,&k); ^ user.cpp:20:33: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(str + 1, MAXN + 5, fi); ^ user.cpp:33:37: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(aux + 1, SIZE + 5, fi); ^