C++基础之用栈计算逆波兰式
print?#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Mystack *Stack;
struct Mystack {
int Capacity; /* 栈的容量 */
int Top_of_stack; /* 栈顶下标 */
int *Array; /* 存放栈中元素的数组 */
};
/* 栈的创建 */
Stack CreateStack(int Max)
{
Stack S;
S = malloc(sizeof(struct Mystack));
if (S == NULL)
printf("Create stack error!\n");
S->Array = malloc(sizeof(char) * Max);
if (S->Array == NULL)
printf("Create stack error!\n");
S->Capacity = Max;
S->Top_of_stack = 0;
return S;
}
/* 释放栈 */
void DisposeStack(Stack S)
{
if (S != NULL)
{
free(S->Array);
free(S);
}
}
/* 判断一个栈是否是空栈 */
int IsEmpty(Stack S)
{
return !S->Top_of_stack;
}
/* 判断一个栈是否满栈 */
int IsFull(Stack S)
{
if (S->Top_of_stack == S->Capacity - 1)
return 1;
else
return 0;
}
/* 数据入栈 */
int Push(int x, Stack S)
{
if (IsFull(S))
printf("The Stack is full!\n");
else
S->Array[S->Top_of_stack++] = x;
}
/* 数据出栈 */
int Pop(Stack S)
{
if (IsEmpty(S))
printf("The Stack is empty!\n");
else
S->Top_of_stack--;
}
/* 将栈顶返回 */
int Top(Stack S)
{
if (!IsEmpty(S))
return S->Array[S->Top_of_stack-1];
printf("The Stack is empty!\n");
return 0;
}
int main()
{
int i, len, result;
char str[100];
printf("Please input the postfix that you want to compute: \n");
scanf("%s", str);
len = strlen(str);
/* 根据序列的长度来创建栈 */
struct Mystack *my_stack = CreateStack(len+1);
for (i = 0; i < len; i++)
{
if (str[i] >= '0' && str[i] <= '9')
Push((int)str[i]-48, my_stack);
else if (str[i] == '+')
{
int x = Top(my_stack);
Pop(my_stack);
int y =Top(my_stack);
Pop(my_stack);
Push(x+y, my_stack);
//printf("%d\n", Top(my_stack));
}
else if (str[i] == '-')
{
int x = Top(my_stack);
Pop(my_stack);
int y = Top(my_stack);
Pop(my_stack);
Push(x-y, my_stack);
//printf("%d\n", Top(my_stack));
}
else if (str[i] == '*')
{
int x = Top(my_stack);
Pop(my_stack);
int y = Top(my_stack);
Pop(my_stack);
Push(x*y, my_stack);
//printf("%d\n", Top(my_stack));
}
else if (str[i] == '/')
{
int x = Top(my_stack);
Pop(my_stack);
int y = Top(my_stack);
Pop(my_stack);
Push(x/y, my_stack);
//printf("%d\n", Top(my_stack));
}
}
printf("The result is: %d\n", Top(my_stack));
Pop(my_stack);
/* A bug */
// DisposeStack(my_stack);
return 0;
}
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Mystack *Stack;
struct Mystack {
int Capacity; /* 栈的容量 */
int Top_of_stack; /* 栈顶下标 */
int *Array; /* 存放栈中元素的数组 */
};
/* 栈的创建 */
Stack CreateStack(int Max)
{
