Question

I'm working through problem set 1 and have a question about some of the comparison terms. What does += and -= mean? everything else in the solution file makes sense to me but I'm struggling with understanding these terms.

Answer 1

can you show the text of the actual problem please?

Answer 2

also what language is this
java, c, c++ ?

Answer 3

in C/C++/java check the following page - scroll down to the section on "Assignment Operators"
http://www.tutorialspoint.com/cprogramming/c_operators.htm

Here is an excerpt:
+= means
"Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand"
example: C += A is equivalent to C = C + A

and
-= means
"Subtract AND assignment operator, It subtracts right operand from the left operand and assign the result to left operand:
example: C -= A is equivalent to C = C - A

There are also other combinations with = like *=, /=, ...

Answer 4

Python supports these "shorthand" notations.

a += b is shorthand for a = a + b. Subtraction, division and multiplication are also supported.

Answer 5

a+=b means a=a+b
a*=b means a=a*b
a/=b means a=a/b
a-=b means a=a-b

a=+b is very different from a+=b so be careful with these typing errors that can lead to very annoying problems.