题是这样的～输入一串长整数 例如12345678 为了表示清楚记为:12,345,687 如123则输出123

#include <iostream>
using namespace std;
int count=0;
int num_len(int num)
{
    int len=0;
    while (num!=0)
    {
        num/=10;
        ++len;
        if (len%3==0)
        {
            ++count;
        }
    }
    return len; //输入数字的位数
}
void main()
{
    int num,len,flag;
    cin>>num;
    len=num_len(num);
    if (len>3)
    {
        
        int size_char=len+count,sign=0,flag;
        bool first=true;
        flag=len%3; //标记第一次出现,的位置
        char *a=new char[len+1];
        char *b=new char[size_char+1];   
        itoa(num,a,10);
        a[len]=0;
        b[size_char]=0;
        int i=0,j=0;
        while (a[i]!=EOF)
        {            
            sign%=3;
            if (j==flag&&first)
            {
                b[j]=',';
                first=false;
                sign=0;
                continue;
            }
            if (sign==0)
            {
                b[j]=',';               
            }
            else
            {
                b[j]=a[i];               
                ++i;               
            }            
            ++j;
            ++sign;
        }            
        cout<<b<<endl;
    }
    else
    {
        cout<<num<<endl;
    }   
}

试了好长时间都没发现是哪里写错了～出现内存错误 细心的朋友帮我看看 谢谢～

谢谢你 时间长了 好多东西就搞混了 以为eof能直接用
不过你没看懂我的意思 今天又仔细把程序看看了 解决了
#include <iostream>
using namespace std;
int count=0;
int num_len(int num)
{
    int len=0;
    while (num!=0)
    {
        num/=10;
        ++len;
        if (len%3==0)
        {
            ++count;
        }
    }
    return len;
}
void main()
{
   
    int num,len;
    cin>>num;
    len=num_len(num);
        
        int size_char=len+count,sign=1,flag;
        bool first=true;
        flag=len%3;        
        char *a=new char[len+1];
        char *b=new char[size_char+1];   
        itoa(num,a,10);
        a[len]='\0';        
        b[size_char]='\0';   
        if (len%3==0)
        {
            first=false;
        }
        int i=0,j=0;
        while (a[i]!='\0')
        {
            if (j==flag&&first)
            {
                b[i]=',';
                first=false;
                sign=1;
                j++;
                continue;
            }        
            sign%=4;
            if (sign!=0)
            {
                b[j]=a[i];
                ++i;

            }
            else
            {
                b[j]=',';
            }
            ++j;
            ++sign;
        }
        cout<<b<<endl;
   
}

[ 本帖最后由 养下就很帅 于 2009-12-27 19:56 编辑 ]