What does '+=' sign mean?
C += A is equivalent to C = C + A
well a += b is a = b + a
eg.x=x+y can be written in short form as x+=y
It is called "Assignment Operator" or " Short Hand Operator" . += can be explained this example int a = a + 1; or int a += 1; Here , Two Step procedures (1) INCREMENT VARIABLE AT RIGHT SIDE variable a is incremented by 1 (2) ASSIGNING VALUE AT LEFT SIDE value of a is assigned at left side to variable a.
+= is shorthand for incrementing with the value at right i.e a+=5; is equivalent to a=a+5; there are shorthand operators for other arithmetic operates as well.
addition and then assignment
it's a shortcut here's an example a=a+1 adds 1 to a just as a+=1 would and a shortcut for adding 1 a++
suppose you have x+=y ; then it means x=x+y ; same thing will be applied for other as * ,-,/ . "+=" in other words you are increment x by y .