Compilare: user.cpp: In function ‘void read()’: user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<a.length(); j++) ^ user.cpp:14:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v); ^ user.cpp:15:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:16:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ user.cpp: In function ‘int main()’: user.cpp:164:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ferma3.in", "r", stdin); ^ user.cpp:165:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ferma.out", "w", stdout); ^ user.cpp: In function ‘void part_2()’: user.cpp:151:44: warning: ‘mem_c’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d %d\n%c", mem_i, mem_j, mem_c); ^