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

by reference is one way: (in this example the memory for i is local to caller())

void caller()
{
    int i = 5;
    foo(&i);
    bar(&i);
    printf("\n final i is %d",i);
}

void foo(int *i)
{
    printf("%d",*i);
    *i += 5;
}

void bar (int *i)
{
    printf("%d",*i);
    *i += 5;
}

global: (usually considered horrible i would have a name more like GLOBAL_I or something)

int i = 0;

void caller()
{
   i=5;
   foo();
   bar();
   printf("\n final i is %d",i);
}

void foo()
{
   printf("%d",i);
   i += 5;
}

 void bar (int i)
 {
      printf("%d",i);
      i += 5;
 }