大数的十进制转换成二进制

#include <cstdio>
#include <iostream>
#include <string.h>


using namespace std;
char sp[100];
int res[100];
int n,length;

bool isAllZero(char* str)
{
    for(int i=0;i<length;i++)
    {
        if((int)str[i]!=0)
        {
            return false;
        }
    }
    return true;
}

int main()
{
    scanf("%s",sp);
    length = strlen(sp);
   //下面把ascii码值转换成整数值 十进制0对应ascii码的48
    for(int i=0;i<length;i++)
    {
        sp[i] -= 48;
    }
    if(isAllZero(sp)) cout<<"0"<<endl;
    int counter = 0;
  //循环直到数组里所有数都为0
    while(!isAllZero(sp))
    {
        int pre = 0;
        for(int i=0;i<length;i++)
        {
           //除2取余
            int temp = (sp[i]+pre*10)/2;
            pre = (sp[i]+pre*10)%2;
            sp[i] = temp;
        }
        res[counter]=pre;
        counter++;
    }
    cout<<"counter is "<<counter<<endl;
    for(int i=counter-1;i>=0;i--)
    {
        cout<<res[i]<<" ";
    }
    return 0;
}