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A few days back someone asked me a question via email which I thought might be useful to others too. So I’m listing that question along with its answer below. Q. I want to write a program such that users enter the value of matrix and each operation (listed below) is performed by functions. I want to use switch structure to call the functions. 1. Rotate the matrix around the diagonal. Example: 1 2 3 ---> 1 4 7 4 5 6 2 5 8 7 8 9 3 6 9 2. Rotate the matrix around the middle row. Example: 1 2 3 ---> 7 8 9 4 5 6 4 5 6 7 8 9 1 2 3 3. Rotate the matrix around the middle column. Example: 1 2 3 ---> 3 2 1 4 5 6 6 5 4 7 8 9 9 8 7 4. Set the upper triangle to zero. Example: 1 2 3 ---> 1 0 0 4 5 6 4 5 0 7 8 9 7 8 9 Ans. The following program does it. Please note that the matrix is declared as global so as to reduce complications in the program. Better way should have been t...

In the previous article Overloading [] Operator , we overloaded the [] operator in a class to access data within the class by indexing method. The operator [] function was defined as below: int myclass:: operator []( int index) { // if not out of bound if (index<num) return a[index]; } As you can see, the above operator function is returning values, hence it could only be used on the right hand side of a statement. It’s a limitation! You very well know that a statement like below is very common with respect to arrays: a[1]=10; But as I said, the way we overloaded the [] operator, statement like the one above is not possible. The good news is, it is very easy to achieve this. For this we need to overload the [] operator like this: int &myclass:: operator []( int index) { // if not out of bound if (index<num) return a[index]; } By returning a reference to the particular element, it is possibl...