bigint.java

java小程序

public class BigInt
{
private int big[];
public BigInt(int a[]){big=a;}
public BigInt(String s)
{
big=new int[36];
int n=s.length()-1;
for(int i=big.length-1;i>=0;i--)
{
if(n<0) break;
char ch=s.charAt(n--);
if(ch>='0'&&ch<='9')
big[i]=(ch-'0');
else
System.out.println("not digit");
}
}
public int[] getBig(){return big;}
public BigInt add(BigInt bi)
{
int b[]=bi.getBig();
int c[]=new int[36];
int carry=0;
for(int i=b.length-1;i>=0;i--)
{
c[i]=big[i]+b[i]+carry;
carry=c[i]/10;
c[i]=c[i]%10;
}
for(int i=big.length-b.length;i>=0;i--)
c[i]=big[i];
return new BigInt(c);
}
public String toString()
{
String s="";
for(int i=0;i<big.length;i++)
s=s+String.valueOf(big[i]);
return s;
}
}