Compilare: user.cpp: In function ‘void cpy_(char*, char*)’: user.cpp:18:20: warning: NULL used in arithmetic [-Wpointer-arith] for( i=1;b[i]!=NULL;i++ ) ^ user.cpp:21:17: warning: NULL used in arithmetic [-Wpointer-arith] for( ;a[i]!=NULL;i++ ) ^ user.cpp:22:13: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[i]=NULL; ^ user.cpp: In function ‘int cmp_(char*, char*)’: user.cpp:29:18: warning: NULL used in arithmetic [-Wpointer-arith] while( a[i]!=NULL && b[i]!=NULL && a[i]==b[i] ) ^ user.cpp:29:32: warning: NULL used in arithmetic [-Wpointer-arith] while( a[i]!=NULL && b[i]!=NULL && a[i]==b[i] ) ^ user.cpp:32:15: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]==NULL && b[i]!=NULL ) ^ user.cpp:32:29: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]==NULL && b[i]!=NULL ) ^ user.cpp:35:19: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]!=NULL && b[i]==NULL ) ^ user.cpp:35:33: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]!=NULL && b[i]==NULL ) ^ user.cpp:38:23: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]==NULL && b[i]==NULL ) ^ user.cpp:38:37: warning: NULL used in arithmetic [-Wpointer-arith] if( a[i]==NULL && b[i]==NULL ) ^ user.cpp: In function ‘void print_(int)’: user.cpp:94:27: warning: NULL used in arithmetic [-Wpointer-arith] for( i=1;v[k].ing[i]!=NULL;i++ ) ^ user.cpp: In function ‘int main()’: user.cpp:102:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "reteta2.in", "r", stdin ); ^ user.cpp:103:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "reteta2.out", "w", stdout ); ^