Question

I am working on some legacy code. I have the following data types:

typedef struct {

    char        *name ;

    ColumnType  type ;

    unsigned    pos ;    //column position in table

    CellData    **data ; //ptr to list of cells in column

}Column ;

struct _table {

    char name[TABLE_NAME_LEN+1] ;

    unsigned int num_rows ;

    unsigned int num_cols ;

    Column  **cols ; //ptr to list of columns

};



struct _table m_

In the source code, there is the following statement:

m_table.cols = new Column*[m_table.num_cols];

I am familiar with new[], but I’m no sure what the multiplication operator is doing there – can any explain?

Answer 1

It’s not multiplication. The symbol * has many, many completely different meanings in C++, all depending on context.

In your case, you’re creating a dynamic array of Column*, i.e. of pointers to Column.

In other words, you’re saying new T[N];, where T = Column*.