Pointer Example
The standard C routine scanf is where most people first see
pointers. In the example below, the data read from standard input is
placed in the variable i
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int i;
scanf("%d", &i);
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Recall that C uses call by value for scalars, which means that (a copy
of) the address of i is passed to scanf. The
scanf routine reads in the data, and places it in the
indicated address.
In general, if a subroutine needs to modify a scalar variable, it
needs to receive the address of that variable as a parameter.
For example,
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#include <stdio.h>
void Add2 (int *iPtr);
int main()
{
int k = 4;
Add2 (&k);
printf("%d\n", k); /* prints 6 */
return 0;
}
void Add2(int *iPtr)
{
*iPtr += 2;
}
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