C++ :

#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
struct node{
    char v;
    struct node *l, *r;
    node(char c){
        v = c;
        l = r = NULL;
    }
};
stack<node*> p;                 // 操作数栈
stack<char> q;                  // 操作符栈
int len;
char str[1010];

/*
  将p栈顶两数与q栈顶一操作符构建一颗二叉树，并压入p栈
*/
int getOrder(char c){
    switch(c){
    case '+': case '-':
        return 0;
    case '*': case '/':
        return 1;
    case '(': case ')':
        return 2;
    }
}
void buildNode(){
    node *t1 = new node(0);
    node *t2 = new node(0);
    char s;

    t2 = p.top(); p.pop();
    t1 = p.top(); p.pop();
    s = q.top(); q.pop();

    node *N = new node(s);
    N->l = t1;
    N->r = t2;

    p.push(N);
}
void PUSH(int &i){
    node *t = new node(str[i]);
    p.push(t);
}
/*
  根据中缀式构建表达式树
*/
void buildTree(){
    int i;
    for(i = 0; i < len; i++){
        if(str[i] >= '0' && str[i] <= '9')
            PUSH(i);
        else if(str[i] == '(')
            q.push('(');
        else if(str[i] == ')'){
            while(q.top() != '(') buildNode();
            q.pop();
        }else{//+-*/
            while(!q.empty() && q.top()!='('
               && getOrder(q.top()) >= getOrder(str[i]))
                buildNode();
            q.push(str[i]);
        }
    }
    while(!q.empty()) buildNode();
}
void PRTraverse(node *t){
    if(t){
        printf("%c",t->v);
        PRTraverse(t->l);
        PRTraverse(t->r);
    }
}
void POTraverse(node *t){
    if(t){
        POTraverse(t->l);
        POTraverse(t->r);
        printf("%c", t->v);
    }
}
int main(){
    int k;
    scanf("%d", &k);
    while(k--){
        scanf("%s", str);
        len = strlen(str);
        buildTree();
        POTraverse(p.top());
        printf("\n");
        PRTraverse(p.top());
        printf("\n");
        p.pop();
    }
    return 0;
}