swap

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[])
{
   int count =9;
   int *countaddr = & count;
   *countaddr =10;
   printf("%d\n",count);
   printf("%d\n",*countaddr+1);
return 0;
}
=========================
#include <stdio.h>
#include <stdlib.h>
void pass(int *a)
{
*a=*a+1;
}
int main(int argc, char *argv[])
{
    int a=3;
    pass(&a);
    printf("%d",a);
return 0;
}
==========================
#include <stdio.h>
#include <stdlib.h>
void pass(int *a,int *b)
{
int t=*a;
*a=*b;
*b=t;
}
int main(int argc, char *argv[])
{
    int a=1,b=2;
    pass(&a,&b);
    printf("%d %d",a,b);
return 0;
}