C Language Tutorials by Ghulam Murtaza Dahar - HTML preview

Explanation of program and figure

1. Code int *pc, p; creates a pointer pc and a variable c. Pointer pc points to some address and that address has garbage value.

Similarly, variable c also has garbage value at this point.

2. Code c=22; makes the value of c equal to 22, i.e.,22 is stored in the memory location of variable c.

3. Code pc=&c; makes pointer, point to address of c. Note that, &c is the address of variable c (because c is normal variable) and pc is the address of pc (because pc is the pointer variable). Since the address of pc and address of c is same, *pc (value of pointer pc) will be equal to the value of c.

4. Code c=11; makes the value of c, 11. Since, pointer pc is pointing to address of c. Value of *pc will also be 11.

5. Code *pc=2; change the contents of the memory location pointed by pointer pc to change to 2. Since address of pointer pc is same as address of c, value of c also changes to 2.