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] != '\0'; 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("\n");
destroy(&st);
}

main()
{
expr();
}