大数加法

//大数加法
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
go:    int i=0,j=0,cn1,cn2,num=0;
    int     *a=new int[100];
    int  *b=new int[100];
    int    answer[100]={0};
    char *numb1=new char[100];
    char *numb2=new char[100];
    int sum(int x,int y);
    cin>>numb1;
    cn1=strlen(numb1);
    cin>>numb2;
    cn2=strlen(numb2);
    for(i=0;i<cn1;i++)
    {   
        a[i]=numb1[i]-'0';
    }
    for(i=0,j=cn1-1;i<j;i++,j--)
    {
        int t=a[i];
        a[i]=a[j];
        a[j]=t;
    }
    for(i=0;i<cn1;i++)cout<<a[i];
    cout<<endl;
    for(i=0;i<cn2;i++)
    {        
        b[i]=numb2[i]-'0';
    }
    for(i=0,j=cn2-1;i<j;i++,j--)
    {
        int t=b[i];
        b[i]=b[j];
        b[j]=t;
    }
    for(i=0;i<cn2;i++)cout<<b[i];
    cout<<endl;
    cout<<setw(cn2+1)        <<numb1<<endl;
    cout<<"+"<<setw(cn1-1)    <<numb2<<endl;
    cout<<"-----------------------------"<<"\n"<<"=";
    if(cn1>=cn2)
    {
        for(i=0;i<cn2;i++)
        {
            if((answer[i]+sum(a[i],b[i]))>=10)
            {
                answer[i+1]=1;
                answer[i]=(answer[i]+sum(a[i],b[i]))%10;
            }
            else
            {
                answer[i]=answer[i]+sum(a[i],b[i]);
            }
        }
        for(i=cn2;i<cn1;i++)
        {
            if((answer[i]+a[i])>=10)
            {
                answer[i+1]=1;
                answer[i]=(answer[i]+a[i])%10;
            }
            else
            {
                answer[i]+=a[i];
            }
        }
        if(cn1==cn2)cn1++;
        for(i=cn1-1;i>=0;i--)
        {
            cout<<answer[i];
        }
        cout<<endl;
    }
    if(cn1<cn2)
    {
        for(i=0;i<cn1;i++)
        {
            if((answer[i]+sum(a[i],b[i]))>=10)
            {
                answer[i+1]=1;
                answer[i]=(answer[i]+sum(a[i],b[i]))%10;
            }
            else
            {
                answer[i]=answer[i]+sum(a[i],b[i]);
            }
        }
        for(i=cn1;i<cn2;i++)
        {
            if((answer[i]+b[i])>=10)
            {
                answer[i+1]=1;
                answer[i]=(answer[i]+b[j])%10;
            }
            else
            {
                answer[i]+=b[i];
            }
        }
        for(i=cn2-1;i>=0;i--)
        {
            cout<<answer[i];
        }
        cout<<endl;   
    }
    system("pause");
    goto go;
    return 0;
}
int sum(int x,int y)
{
    return x+y;
}