Compilare: user.cpp: In function ‘int main()’: user.cpp:28:24: warning: statement has no effect [-Wunused-value] d[i][j]==-2; ^ user.cpp:20:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d\n",&n); ^ user.cpp:22:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(1+a[i],256,in); ^