Program of Persistent variables:
The program below elaborates this. The script calls a function func1 that initializes a variable count to 0, then increment it, and print the value. Each and every time this function is called, the variable is formed, initialized to 0, changed to 1, and then cleared whenever the function exits. The script then calls a function func2 that first declares a persistent variable count. When the variable has not yet been initialized, that will be the case the first time the function is called, it is initialized to 0. Now, like the first function, the variable is then incremented and the value is printed. With the second function, though, when the function exits, the variable remains with its value, therefore the next time the function is called the variable is incremented again.