In C programming, static is a reserved keyword which controls both lifetime as well as visibility. If we declare a variable as static inside a function then it will only visible throughout that function. In this usage, this static variable's lifetime will start when a function call and it will destroy after the execution of that function. you can see the following example:
#include<stdio.h>
int counterFunction()
{
static int count = 0;
count++;
return count;
}
int main()
{
printf("First Counter Output = %d\n", counterFunction());
printf("Second Counter Output = %d ", counterFunction());
return 0;
}
Above program will give us this Output:
First Counter Output = 1
Second Counter Output = 1
Because as soon as we call the function it will initialize the count = 0. And while we execute the counterFunction it will destroy the count variable.