Compilare: main.cpp: In function 'int main()': main.cpp:205:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "bmatrix.in", "r", stdin ) ; ^ main.cpp:206:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "bmatrix.out", "w", stdout ) ; ^ main.cpp:210:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d", & n, & m ) ; ^ main.cpp:214:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%1d", & a [ i ] [ j ] ) ; ^