找不到哪里错了

#include <iostream>
#include <cmath>
using namespace std;
const int MAX=15;

struct AddNum{
	int num1, num2;
};
int add(AddNum num){
	int a[MAX];//用来存储加数的
	int b[MAX]={num.num1, num.num2};//例：._num1 = 1, ._num2=2, b[5]={1, 2}
	for(int i=0;i<2;i++){
		a[i]=b[i];
	}
	return max(a[0], a[1])+min(a[0], a[1]);
} 
AddNum CharToInt(char character1, char character2){
	AddNum Sum;
	Sum.num1=character1-'0';
	Sum.num2=character2-'0';
	return Sum;
}
int main(){
    char Sum1, Sum2;
    AddNum add;
    cin>>Sum1>>Sum2;
    add=CharToInt(Sum1, Sum2);//把字符Sum1与Sum2转换成数字分别复制到add.num1和add.num2 
    cout<<add.num1+add.num2;
    return 0;

}