8.2 Compound Subtraction and Assignment

void operator-=(int x, int y)
x -= y is equivalent to x = x - y.

void operator-=(real x, real y)
x -= y is equivalent to x = x - y.

void operator-=(vector x, real y)
x -= y is equivalent to x = x - y.

void operator-=(row_vector x, real y)
x -= y is equivalent to x = x - y.

void operator-=(matrix x, real y)
x -= y is equivalent to x = x - y.

void operator-=(vector x, vector y)
x -= y is equivalent to x = x - y.

void operator-=(row_vector x, row_vector y)
x -= y is equivalent to x = x - y.

void operator-=(matrix x, matrix y)
x -= y is equivalent to x = x - y.