SDUT-2484 算术表达式的转换

 

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define Maxsize 1000
typedef char Elementtype;

struct node
{
    Elementtype * data;
    int top;
    int maxsize;
};

int Initstack(struct node * Stack)
{
    Stack->data = (Elementtype *) malloc( Maxsize * sizeof(Elementtype) );
    if(Stack->data == NULL) return 0;
    Stack->maxsize = Maxsize;
    Stack->top = -1;
    return 1;
}

int Full(struct node * Stack)
{
    return (Stack->top == (Stack->maxsize - 1));
}

int Push(Elementtype k, struct node * Stack)
{
    if(Full(Stack))
    {
        printf("The stack is full.\n");
        return 0;
    }
    else
    {
        Stack->data[++Stack->top] = k;
    }
    return 1;
}

int IsEmpty(struct node * Stack)
{
    return (Stack->top == -1);
}

Elementtype Pop(struct node * Stack)
{
    if(IsEmpty(Stack))
    {
        printf("The stack is empty.\n");
        return 0;
    }
    else
    {
        return Stack->data[Stack->top--];
    }
}

Elementtype GetTop(struct node * Stack)
{
    return Stack->data[Stack->top];
}

void Deletestack(struct node * Stack)
{
    free(Stack->data);
    Stack->top = -1;
    Stack->maxsize = -1;
}

int main()
{
    struct node S1, S2;
    char c[1001];
    Initstack(&S1);
    Initstack(&S2);
    gets(c);
    int i, len = strlen(c);
    for(i = len - 2; i >= 0; i--)
    {
        switch(c[i])
        {
        case '(':
            char d;
            while(1)
            {
                d = Pop(&S1);
                if(d == ')') break;
                Push(d, &S2);
            }
            break;
        case '-':
        case '+'://前缀++ab
            while(GetTop(&S1) != ')' && !IsEmpty(&S1) && GetTop(&S1) != '+' && GetTop(&S1) != '-')
            {
                Push(Pop(&S1), &S2);
            }
            Push(c[i], &S1);
            break;
        case '*':
        case '/':
        case ')':
            Push(c[i], &S1);
            break;
        default:
            Push(c[i], &S2);
        }
    }
    while(!IsEmpty(&S1))
    {
        char d = Pop(&S1);
        Push(d, &S2);
    }
    while(!IsEmpty(&S2))
    {
        putchar(Pop(&S2));
    }
    putchar('\n');
    Deletestack(&S1);
    Deletestack(&S2);
    for(i = 0; c[i] != '#'; i++)
    {
        if(c[i] != '(' && c[i] != ')')
        putchar(c[i]);
    }
    putchar('\n');
    Initstack(&S1);
    for(i = 0; c[i] != '#'; i++)
    {
        switch(c[i])
        {
        case ')':
            char d;
            while(1)
            {
                d = Pop(&S1);
                if(d == '(') break;
                putchar(d);
            }
            break;
        case '+':
        case '-':
            while(GetTop(&S1) != '(' && !IsEmpty(&S1))
            {
                putchar(Pop(&S1));
            }
            Push(c[i], &S1);
            break;
        case '*':
        case '/':
            if(!IsEmpty(&S1) && GetTop(&S1) != '(' && GetTop(&S1) != '+' && GetTop(&S1) != '-')
                {putchar(GetTop(&S1)); Pop(&S1);}
        case '(':
            Push(c[i], &S1);
            break;
        default:
            putchar(c[i]);
        }
    }
    while(!IsEmpty(&S1))
    {
        putchar(Pop(&S1));
    }
    putchar('\n');
    return 0;
}