Reading notes _effective_c++_ clause 21: When you must return an object, don't be paranoid about returning it reference

Temporary member variable in stack space cannot be transmitted after the end of the function lifetime

operator* (constconst a& b) {    A temp;     = A.data*b.data; // Multiply the member variables of a, b    return temp;}

Since the stack space is not good, try the heap space

operator* (constconst a& b) {    *temp=new  A;     = A.data*b.data; // Multiply the member variables of a, b    return *temp;}

Not, because you may forget yourself new, even if you have not forgotten, but appear ((a*b) *c) Situation will make you cannot delete

operator* (constconst a& b) {    staticnew  A;     = A.data*b.data; // Multiply the member variables of a, b    return temp;}

Attempts to derive immortality with global variables, but the presence of if ((a*b) = = (c*d) will be constant

There is no way, pass-by-reference, although good, please don't top, this time we honestly use Pass-by-value

Reading notes _effective_c++_ clause 21: When you must return an object, don't be paranoid about returning it reference