More Samples of Identifier Scopes

int A = 7;       // global variable declaration
int B = 8;       // global variable declaration
int C = 9;       // global variable declaration

void F1(void);   // function declaration
void F2(void);   // function declaration

void main(void)
{
  // local variables in main
  // they "hide" the global variables a, b, c
  int A, B, C;

  A = 10;  // has no effect on global A
  . . .
}

void F1(void)
{
  // local variables in F1
  int x, y, z; 

  x = A;   // now, x has same value as A (7)
  y = B;   // now, y has same value as B (8)
  z = C;   // now, z has same value as C (9)
}

void F2(void)
{
  // local variables in F2
  // NOT the same as the ones in F1 above
  int x = 1, y = 2, z = 3;

  A = x;   // now, A has same value as x (1)
  B = y;   // now, B has same value as y (2)
  C = z;   // now, C has same value as z (3)
}