1. Static vs Dynamic Scope
Mark Boady

2. Scopes Static Scope Dynamic Scope
Determine Variable Scope at compile time
Dynamic Scope
Determine Variable Scope at run time
Static Scope is most likely what you are used to

3. Example 1
int x; int main(){ x=2; f(); g(); h(); } Void f() { int x=3; h();} Void g() { int x=4; h();} Void h() { printf(“%d ”,x);} Static Prints out: Dynamic Prints out: 3 4 2

4. Example 2
Int m,n; Void hardy(){ printf(“in hardy n =%d”,n); } Void laurel(int n){ printf(“in laurel m=%d\n”,m); printf(“in laurel n=%d\n”,n); Hardy(); } Int main(){ m=50; n=100; printf(“In Main n=%d”,n); Laurel(1); hardy();

5. Example 2 Static Answer in main program -- n = 100 in laurel -- m = 50
in laurel -- n = 1
in hardy -- n = 100

6. Example 2 Dynamic Answer
in main program -- n = 100
in laurel -- m = 50
in laurel -- n = 1
in hardy -- n = 1
in hardy -- n = 100