1.栈的简介
栈是一种后入先出的数据结构,一般包含两种最基本的操作:入栈(push)和出栈(pop)。
入栈操作:top指针上移,元素入栈。
出栈操作:top指针下移。
栈空的条件:top == bottom
栈满的条件:top == maxsize-1
2.有数据序列1 2 3一次存入一个栈stack中,则出栈顺序可以为以下四种:
1,2,3; 2,1,3; 3,2,1; 1,3,2.
3.任意输入一个十进制整数x(x<32768),输出x的二进制值。
#include <stdio.h>
#define MAXSIZE 15
int main()
{
int a[MAXSIZE];
int bottom, top;
int x;
bottom = top = -1;
printf("Please input x(0<=x<=32767):");
scanf("%d", &x);
while(x)
{
a[++top] = x%2;
x /= 2;
}
while(-1 != top)
{
printf("%d ", a[top--]);
}
printf("\n");
return 0;
}
4.判断一个C语言表达式的左右括号是否匹配,提示:将要判断的表达式用字符串输入。
#include <stdio.h>
#define MAXSIZE 100
int main()
{
char a[MAXSIZE];
int top = -1;
int i;
printf("Please input a expression:");
gets(a);
i = 0;
while(a[i])
{
if('(' == a[i])
top ++;
else if(')' == a[i])
{
if(-1 == top)
break;
else
top --;
}
i ++;
}
if('\0' == a[i] && -1 == top)
printf("Match.\n");
else
printf("Not match.\n");
return 0;
}
5.栈的基本操作——出栈和入栈
#include <stdio.h>
#include <malloc.h>
typedef struct st
{
int maxsize;
int top;
int *pstack;
}stack;
void create_stack(stack *s, int ms);
void push(stack *s, int x);
int pop(stack *s);
void clear_stack(stack *s);
int main()
{
stack s;
int ms, i;
int a[] = {13, 17, 15, 25};
printf("Please input stack size:");
scanf("%d", &ms);
create_stack(&s, ms);
for(i = 0; i < 4; i++)
push(&s, a[i]);
while(s.top != -1)
printf("%d ", pop(&s));
printf("\n");
clear_stack(&s);
return 0;
}
void create_stack(stack *s, int ms)
{
s->maxsize = ms;
s->top = -1;
s->pstack = (int *)malloc(ms*sizeof(int));
}
void push(stack *s, int x)
{
if(s->top < s->maxsize-1)
s->pstack[++s->top] = x;
}
int pop(stack *s)
{
if(s->top != -1)
return s->pstack[s->top--];
}
void clear_stack(stack *s)
{
s->maxsize = 0;
s->top = -1;
free(s->pstack);
s->pstack = 0;
}