Assignment Operator:

The simple assignment operator (=) assigns the right side to left side.

C++ provides shorthand operators that have the capability of performing an operation and an assignment at the same time.
For example:

int x=5;  
x+=3;  //It's mean x=x+3  
x-=2;  //It's mean x=x-2  
x*=2;  //It's mean x=x*2  
x/=3;  //It's mean x=x/2  
Increment Operator:

The increment operator is used to increase an integer value by one, and is a commonly used C++ operator.

x++;  //It's mean x=x+1  

For example:

int x=10;  
x++;  
cout<<x;  

Output:

11  

The increment operator has two forms, prefix and postfix.

++x;  //prefix
x++;  //postfix  

Prefix: Prefix increments the value, and then proceeds with the expression.

Postfix: Postfix evaluate the expression and then performs the increment.

Prefix example:

x=4;  
y=++x;  //x is 4, y is 5  
Decrement Operator:

The decrement operator (-) works in much the same way as the increment operator, but instead of increasing the value, it decreases it by one.

--x;  //prefix
x--;  //postfix