computer
If
int main()
{
int a=1;
int *p;
how do the following statements differ
1) p=&a;
2) *p=&a;
3) p=a;
4) printf("%d",p);
5) printf("%d",*p);
and what does int **a mean
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Answers
The statement 1) p=&a; assigns the memory address of the variable a to the pointer *p. The statement 2) *p=&a; is invalid syntax, since *p is a pointer, not a memory address. The statement 3) p=a; assigns the value of a to the pointer p. The statement 4) printf("%d",p); prints out the memory address stored in the pointer p. The statement 5) printf("%d",*p); prints out the value stored in the memory address pointed to by the pointer p. int **a means that a is a pointer to a pointer to an int. This means that a contains the memory address of a pointer to an int. The value stored in the memory address stored in a can be accessed by dereferencing twice (*a and **a).
