Compilare: user.cpp: In function ‘int main()’: user.cpp:54:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.in", "r", stdin); ^ user.cpp:55:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.out", "w", stdout); ^ user.cpp:59:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:62:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1; j<=M; j++) {scanf("%d",&A[i][j]); MAX=max(MAX,A[i][j]);} ^ user.cpp:89:43: warning: ‘C_max’ may be used uninitialized in this function [-Wmaybe-uninitialized] TRASEU(L_max,C_max,DRUM[L_max][C_max]); ^ user.cpp:89:43: warning: ‘L_max’ may be used uninitialized in this function [-Wmaybe-uninitialized]