Compilare: user.cpp: In function ‘void read()’: user.cpp:19:34: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a + 1, maxM - 2, stdin); ^ user.cpp:20:34: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(b + 1, maxM - 2, stdin); ^ user.cpp: In function ‘void write()’: user.cpp:113:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &m); ^ user.cpp:116:38: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s + 1, maxM - 2, stdin); ^