Compilare: main.cpp: In function 'int main()': main.cpp:191:44: 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:192:46: 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:196:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , & n , & m ) ; ^ main.cpp:200:47: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%1d" , & a [ i ] [ j ] ) ; ^