数据结构：中缀表达式转后缀表达式

#include <stdio.h>
#include "SqStack2.h"
#define STACKTYPE SqStack

#define BOOL int
#define TRUE 1
#define FALSE 0

BOOL isnumeric(char c)
{
    return (c >= '0' && c <= '9') ? TRUE : FALSE;
}

int lv(char c)
{
    int wt[] = {3,0,2,1,-1,1,-1,2};
    return wt[c - '('];
}

void expr()
{
    char ex[] = "10+(3+4)*(12-6)";
    int i,n;
    BOOL isNumber = FALSE;//上一个字符是否是数字，连续两个数字要合并
    STACKTYPE st;
    init(&st);
    for (i = 0; ex[i] != ''; i++) {
        if (isnumeric(ex[i])){
            if (isNumber == FALSE) printf(" ");
            printf("%d", ex[i]-'0');
            isNumber = TRUE;
        }
        else {
            isNumber = FALSE;
            if (ex[i] == ')'){//如果是右括号，则匹配栈中第一个左括号
                n = ' ';
                do {
                    if (n != ' ') printf(" %c", n);
                } while (pop(&st, &n)==OK && n != '(');
            }
            else if (ex[i] == '(') {//左括号直接入栈
                push(&st, ex[i]);
            }
            else {//其他运算符，输出栈中所有优先度更高的运算符
                while (getTop(st, &n) == OK && n != '(' && lv(n) >= lv(ex[i]))
                    pop(&st, &n);
                push(&st, ex[i]);
            }
        }
    }

    while (pop(&st, &n) == OK)
        printf(" %c", n);

    printf("
");
    destroy(&st);
}

main()
{
    expr();
}