C语言利用栈实现将中缀表达式转换为后缀表达式（即逆波兰式）

来源：互联网发布：淘宝图片空间怎么导出编辑：程序博客网时间：2024/05/19 02:28

输入计算表达式如：（1-3）*4+10/5

输出的逆波兰式：1 3 - 4 * 10 5 / +

码代码时脸上洋溢着的神秘的微笑

#include <stdio.h>#include <stdlib.h>#include <ctype.h>#define Stack_Init_Size 20#define Stack_Increasement 10typedef char Elemtype;typedef struct{    Elemtype *base;    Elemtype *top;    int stacksize;}sqStack;void initStack(sqStack *s){    s->base=(Elemtype *)malloc(Stack_Init_Size*sizeof(Elemtype));    if(!s->base)    {        return;    }    s->top=s->base;    s->stacksize=Stack_Init_Size;}void push(sqStack *s,Elemtype e){    if(s->top-s->base>=s->stacksize)    {        s->base=(Elemtype *)realloc(s->base,(Stack_Increasement+s->stacksize)*sizeof(Elemtype));        if(!s->base)        {            return;        }    }    *(s->top)=e;    s->top++;}void pop(sqStack *s,Elemtype *e){    if(s->top == s->base)    {        return;    }    s->top--;    *e=*(s->top);}int stackLen(sqStack s){    return (s.top-s.base);}int isEmpty(sqStack s){    return (s.base==s.top);}int main(){    sqStack s;    initStack(&s);    char c,e;    printf("请输入所要计算的中缀表达式，以#结束！\n");    scanf("%c",&c);    while(c!='#')    {        while(isdigit(c))        {            printf("%c",c);            scanf("%c",&c);  //如果此刻输入#，则外层以#为结束条件的循环会无法结束，因为后面有读入的语句，此时读入的#会被“覆盖”，所以外层循环内的要判断读入的c是否是#            if(c>'9'||c<'0')            {                printf(" ");            }        }  //保证输出的多位数的形式正确  如123不会输出1 2 3        if(')'==c)        {            pop(&s,&e);            while( '(' != e )            {                printf("%c ",e);                pop(&s,&e);            }        }        else if('+'==c ||'-'==c)        {            if(isEmpty(s))            {                push(&s,c);            }            else            {                do                {                    pop(&s,&e);                    if( '(' == e )                    {                       push(&s,e);                    }                    else                    {                        printf("%c ",e);                    }                }while(!isEmpty(s) && '('!=e);                push(&s,c);            }        }        else if( '*' == c || '/' == c || '(' == c )        {             push(&s,c);        }        else if('#'==c)        {            break;        }        else        {            printf("\n出错：输入格式错误！\n");            return -1;        }        scanf("%c",&c);    }    while(!isEmpty(s))    {        pop(&s,&e);        printf("%c ",e);    }printf("\n");    return 0;}

1 0