How to share a variable between two functions in C?

Question

In C, suppose var1 is a variable in foo1() and foo2() wants to access var1, however, foo1() doesn\'t call foo2(), so we can\'t pass it by parameter. At the same time, only foo1(

Answer 1

you pass the variable to both functions.... in general functions shouldn't hold state.

quickly you find passing variables is not so nice and becomes fragile, so instead, you pass structs.... then functions start working on the state of structs.

typedef struct 
{
    int var1;
} blah_t;

void foo1(blah_t* b)
{
    b->var1=0;
}

void foo2(blah_t* b)
{
    b->var1++;
}

this is the very simplistic seed idea behind doing OO C.