Solution for Exercise 16-6

ex1606

#include <stdio.h>

void proc(void);

int main()
{
    puts("First call");
    proc();
    puts("Second call");
    proc();
    return(0);
}

void proc(void)
{
    static int a;

    printf("The value of variable a is %d\n",a);
    printf("Enter a new value: ");
    scanf("%d",&a);
}

Output

First call
The value of variable a is 0
Enter a new value: 6
Second call
The value of variable a is 6
Enter a new value: 5

Notes

* A static variable's contents are retained after its function quits. It might seem like all variables should be declared that way, but memory was tight on computers when the C language was developed.

* Variables declared as static are initialized to zero. This is a compiler feature. It explains why the value you see in the output is zero, and not garbage, as well as why the compiler doesn't generate a warning about using an uninitialized variable.

Exercise ex1607 →