INC 161 , CPE 100
     Computer Programming
        Lecture 10
      Scope of Variables
          Global and Local Variables
    Although it is not recommended, global variables shared by different 
    functions  can be used to communicate between functions. 
    The same identifiers can be used in different scopes. The values of the 
    variables are stored in different memory locations.
     Example global        /* File: global.c */
                           #include 
                           int g = 10;   // global variable 
     Output:               void func1(void) {            Global variable
                              g++;
                              printf("g in func1() = %d\n", g);
    g in func1() = 11      }
    g in func2() = 12      void func2(void) {
    g in func3() = 1          g++;
    g in main() = 12          printf("g in func2() = %d\n", g);
                           }
                           void func3(void) {
                              int g=0;   // local variable
     g is the same            g++;
     is all functions         printf("g in func3() = %d\n", g);
     because it is a       }
                           main() {
     global variable          func1();
                              func2();
                              func3();
                              printf("g in main() = %d\n", g);
                           }
     Example local         /* File: local.c */
                           #include 
     Output:               void func1(void) {
                             int g = 1;  //try removing this line later
                             g++;
                             printf("g in func1() = %d\n", g);
                           }
                           main() {
                             int g = 1;
                             printf("g in main before func1() = %d\n", g);
    g is different           func1();
                             printf("g in main after func1() = %d\n", g);
    when it is in          }
    different {..} pair
                  g in main before func1() = 1
                  g in func1() = 2
                  g in main after func1() = 1