Compilare: user.cpp: In function ‘int main()’: user.cpp:50:45: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d%d%d ", &n, &m, &l, &k); ^ user.cpp:52:28: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s+1, MAXN+5, fin); ^ user.cpp:66:32: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(e+1, MAXL+5, fin); ^