WA on #3 #9 #10,code:

#include <iostream>
#include <cctype>
#include <cmath>

const int N = 105;

int St[N];
char st[N];

bool higher(char c,char _c){
    
    if (c == '+' || c == '-') return false;
    if (c == '*' || c == '/') return _c == '+' || _c == '-';

    return true;
}

int main(){

    #ifndef ONLINE_JUDGE
        freopen("P1175.in","r",stdin);
        freopen("P1175.out","w",stdout);
    #endif

    std::cin.tie(0)->sync_with_stdio(0);

    int top = 0;
    std::string in,post = "";

    std::cin >> in;
    for (char c : in){

        if (isdigit(c)) post += c,post += ' ';
        else{

            if (c == '(') st[++top] = c;
            else if (c == ')'){

                while (top && st[top] != '(') 
                    post += st[top],post += ' ',--top;
                if (top) --top;

            }
            else if (!top || st[top] == '(' || higher(c,st[top])) st[++top] = c;
            else{

                while (top && st[top] != '(' && !higher(c,st[top])) 
                    post += st[top],post += ' ',--top;
                st[++top] = c;

            }

        }

    }
    while (top) post += st[top],post += ' ',--top;
    post.pop_back();
    std::cout << post << '\n';

    for (int i = 0;i < post.length();i++){

        if (isdigit(post[i])) St[++top] = post[i] - '0';
        else if (post[i] != ' '){

            int a = St[top--],b = St[top--],tmp,pos = i - 2;

            switch (post[i]){

                case '+':tmp = b + a;break;
                case '-':tmp = b - a;break;
                case '*':tmp = b * a;break;
                case '/':tmp = b / a;break;
                case '^':tmp = pow(b,a);break;
                default:break;

            }
            St[++top] = tmp;
            post.erase(i - 1,2);
            while (pos >= 0 && isdigit(post[pos])) post.erase(pos,1),pos--;
            post.erase(std::max(pos,0),1);
            pos--;
            while (pos >= 0 && isdigit(post[pos])) post.erase(pos,1),pos--;
            post.erase(std::max(pos,0),1);
            pos--;
            if (pos + 1 >= 0) post.insert(pos + 1,' ' + std::to_string(tmp));
            else post.insert(0,std::to_string(tmp) + ' ');
            i = std::max(pos + 2,0) + std::to_string(tmp).length();
            std::cout << post << '\n';
            
            
        }

    }

    return 0;
}

最好能告诉我错因，或者告诉我哪行错了也行