An ASSERT statement is used to check the value of a single variable at a particular location in the program. It may be placed at any point that a C++ / Java statement could be placed. In the following example, an ASSERT statement is used to insure that the variable x does not have a negative value after the assignment statement.
. . . . x = y ; ASSERT( x >= 0, "x has a negative value") ; cout << "Value of x is " << x << endl ; . . . .
ASSERT statements are useful to verify that values computed within methods/functions are within acceptable bounds. An ASSERT statement may only be used as a Definition Placed assertion.