go语言实现stack

golang

package stack
import (
  "errors"
)
type Stack []interface{}
func(stack *Stack) Push(v interface{}) {
  *stack = append(*stack, v)
}
func(stack *Stack) Pop() (interface{}, error){
  if len(*stack) == 0 { 
    return nil, errors.New("stack empty")
  }  
  v := (*stack)[len(*stack) - 1]
  *stack = (*stack)[:len(*stack) - 1]
  return v, nil 
}
func(stack *Stack) Top() (interface{}, error) {
  if len(*stack) == 0 { 
    return nil, errors.New("stack empty")
  }  
  return (*stack)[len(*stack) - 1], nil 
}
func(stack *Stack) Len() int {
  return len(*stack)
}

同样的思路用c实现:

typedef struct my_stack_t my_stack_t;
struct my_stack_t {
  void **s; /* 元素为void *的数组 */
  int use;  /* 已存入的元素个数 */
  int size; /* 在内存中已分配的个数 */
  void (*do_free)(void *);
};
#define DEFAULT_N 100
int stack_init(my_stack_t *s, void (*do_free)()) {
  assert(s != NULL);
  s->s = (void **)malloc(sizeof(void *) * DEFAULT_N);
  s->use = 0;
  s->size = DEFAULT_N;
  s->do_free = do_free;
  return 0;
}
int stack_push(my_stack_t *s, void *v) {
  assert(s != NULL);
  char *p; 
  if (s->use == s->size) {
    p = realloc(s->s, s->size * 2); 
    if (p == NULL)
      return -1; 
    s->size *= 2;
  }  
  s->s[s->use++] = v;
  return 0;
}
void *stack_pop(my_stack_t *s) {
  assert(s != NULL);
  if (s->use == 0) {
    return NULL;
  }  
  return s->s[--s->use];
}
void *stack_top(my_stack_t *s) {
  assert(s != NULL);
  if (s->use == 0) {
    return NULL;
  }  
  return s->s[s->use - 1]; 
}
int stack_len(my_stack_t *s) {
  return s->use;
}
int stack_free(my_stack_t *s) {
  void *v;
  if (s->do_free == NULL) {
    return 0;
  }
  while ((v = stack_pop(s)) != NULL) {
    s->do_free(s);
  }
  return 0;
}

*golang里的interface{} 等同于c里的void *

本文来自:开源中国博客

感谢作者:guonaihong

查看原文:go语言实现stack

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