x += c++

The expression "x += c++" in C++ is a compound assignment statement that performs the addition and assignment operation in a single step. Here's an explanation of each step:

1. The variable "c++" is a post-increment operator. It increments the value of "c" by 1 after the statement is executed.

2. The value of "c" is added to the value of "x". This is equivalent to "x = x + c".

3. The result of the addition is then assigned back to the variable "x".

In summary, the expression "x += c++" increments the value of "c" by 1, adds the incremented value of "c" to the current value of "x", and assigns the result back to "x".