后缀表达式求值

#include <stdio.h>
#include <string.h>
#include "STACK.h"


int main(int argc, char *argv[])
{
  char *a = argv[1]; int i, N = strlen(a);

  STACKinit(N);

  for (i = 0; i < N; i++)
    {
      if (a[i] == '+')
        STACKpush(STACKpop()+STACKpop());
      if (a[i] == '*')
        STACKpush(STACKpop()*STACKpop());
      if ((a[i] >= '0') && (a[i] <= '9'))
        STACKpush(0);
      while ((a[i] >= '0') && (a[i] <= '9'))
        STACKpush(10*STACKpop() + (a[i++]-'0'));
    }
  printf("%d \n", STACKpop());

  return 0;
}


其中STACKpush,STACKpop,STACKinit为对下推栈的操作函数