Increment and decrement expressions

AWK also supports the increment++ and decrement-- operators; they increase or decrease the value of a variable by one.Both operators are similar to the operators in C. These operators can only be used with a single variable and, thus, only before or after the variable.They are the short forms of some common operations of adding and subtracting.

Pre-increment:

It is represented by the plus plus (++) symbolprefixed to the variable. It increments the value of an operand by one. Let's say we have a variable, var; to pre-increment its value, we write ++var.It first increments the value of operand and then returns the incremented value. In the following example, we use two variables,p =5andq = ++p.Here, first the value is incremented and then it is assigned. So,the pre-increment sets both the operands p and q to 6.It is equivalent to p=p+1 and then q=p, as follows:

$ vi pre-increment.awk

BEGIN    { 
    p = 5;
    q = ++p;
    printf "p = %d, q = %d\n", p,q
 ...