// just needed so you actually can compile this with gcc
typedef unsigned long uint64_t;
// for passing an argument and receiving a return value
uint64_t arg;
void
getui()
{
// implementation of subprogram getui
scanf("%lu", &arg);
}
void
puts()
{
// implementation of subprogram puts
printf("%s", arg);
}
void
putui()
{
// implementation of subprogram putui
printf("%lu", arg);
}
// some string literal
char msg[] = "You typed: ";
void
main()
{
// local variable
uint64_t n;
// call subprogram getui, copy return value to local variable
getui();
n = arg;
// copy pointer to string literal to arg, call puts
arg = msg;
puts();
// copy local variable to arg, call putui
arg = n;
putui();
}