矩阵链乘之结构体构造函数

struct Dog {    Dog()    {        name = "wangwang";        age = 10;    }    string name;    int age;};

struct Dog {    Dog()    {        name = "Ao di";        age = 2;    }    Dog(string n)    {        name = n;        age = 10;    }    Car(string n, int c)    {        name = n;        age = c;    }    string name;    int age;};

struct Dog {    Dog(string n = "Lihao", int c = 10) : name(n), age(c) {} //name = n, age = c    string name;    int age;};

#include<iostream>#include<cstdio>#include<cstring>#include<stack>#include<string>using namespace std;#define maxn 30struct matrix{    int a, b;    matrix(int a=0, int b=0) :a(a), b(b){} //神奇的构造函数。}mat[maxn];int main(){    int m;    cin >> m;    for (int i = 0; i < m; i++){        char name;        cin >> name;        cin >> mat[name - ‘A‘].a >> mat[name - ‘A‘].b;    }        char exp[200];    stack<matrix> s;    while (cin >> exp){        int len = strlen(exp);        bool error = false;        int ans = 0;        for (int i = 0; i < len; i++){            if (exp[i] >= ‘A‘&&exp[i] < ‘Z‘)                s.push(mat[exp[i] - ‘A‘]);            else if (exp[i] == ‘)‘){                matrix m1 = s.top(); s.pop();                matrix m2 = s.top(); s.pop();                if (m2.b != m1.a) { error = true; break; }                ans += m2.a*m1.a*m1.b;               s.push(matrix(m2.a, m1.b));//初始化之后，系统会生成一个指向该结构体的地址。            }        }        if (error) cout << "error" << endl;        else cout << ans << endl;    }    return 0;}