Compilare: user.cpp:37:30: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] char line[MAX_LINE] = { NULL }; ^ user.cpp:39:45: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] char characterMatrix[MAX_N][MAX_N] = { NULL }; ^ user.cpp: In function ‘void Read()’: user.cpp:67:40: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d %d", &n, &m, &k); ^ user.cpp:71:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%s", &line[0]); ^