Compilare: user.cpp: In function ‘void back()’: user.cpp:11:23: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if ((i>>j)&1==1) nrcol++; ^ user.cpp:13:23: warning: variable ‘b’ set but not used [-Wunused-but-set-variable] int ii,jj,b,sumlin=0,lin[7300]={0}; ^ user.cpp: In function ‘int main()’: user.cpp:26:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("elimin.in","r",stdin); ^ user.cpp:27:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("elimin.out","w",stdout); ^ user.cpp:28:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&n,&m,&x,&y); ^ user.cpp:32:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t[i][j]); ^ user.cpp:36:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t[j][i]); ^