重载-.cpp

巨型整数类

#include"head.h"

HugeInt operator-(const HugeInt &a,const HugeInt &b){
	HugeInt h1,h2,h,m,n;  //初始构造为0,m和n用来保存a和b，避免a，b改变
	h1=a; h2=b; m=a; n=b;
    int flag; //记录如果a<b则置1
	
	
	if(h1>=h2){  //当a>=b的情况
		flag=0;
		if(h1>=h && h2<=h){
			h=h1+(-h2);
			return h;
		}
		if(h1<=h && h2<=h){
			h1=-n; h2=-m;
		}
	}
	if(h1<h2){  //当a<b的情况
		flag=1;
		if(h1>=h && h2>=h) {
			h1=n; h2=m;
		}
		if(h1<h && h2>h){  //当a<0,b>0的情况
			h1=-h1;
			return -(h1+h2);
		}
		if(h1<h && h2<h){ //当a<b<0的情况
			h1=-h1; h2=-h2;
		}
	}
	
	for( int i=1; i<=h2.huge_t[0]; i++){  //相减为负，则向高位借一, 默认a>=b>=0
		h1.huge_t[i]-=h2.huge_t[i];
		if(h1.huge_t[i]<0){
			h1.huge_t[i]+=Depth;
			h1.huge_t[i+1]--;
			
		}
	}
	for( ; h1.huge_t[i]<0 ; h1.huge_t[i]+=Depth,i++,h1.huge_t[i]-- );
	
	for( ; !h1.huge_t[ h1.huge_t[0] ] && h1.huge_t[0]>1 ; h1.huge_t[0]-- );  //高位为0则消去
	if(flag==1) return -h1;   //结果为负则置反
	return h1;
}

//--------------------巨型整数-长整型整数----------------------//
HugeInt operator-(const HugeInt &h,const long &n){
	HugeInt h1,h2;
	h1.long_to_huge(n,h1);
	return h2=h-h1;
}

//-------------------巨型整数-字符串----------------------------//
HugeInt operator-(const HugeInt &h,const char *buf){
	HugeInt h1,h2;
    char str[MAX*Digit + 1];
    strcpy(str,buf);
	h1.str_to_huge(str,h1);
	return h2=h-h1;
}

//-------------------字符串-巨型整数--------------------------//
HugeInt operator-(const char *buf,const HugeInt &h){
	HugeInt h1,h2;
	char str[MAX*Digit + 1];
	strcpy(str,buf);
	h1.str_to_huge(str,h1);  //字符串转化成巨型整数
	return h2=h1-h;
}

//-----------------长整型-字符串----------------------------//
HugeInt operator-(const long &n,const HugeInt &h){
	HugeInt h1,h2;
	h1.long_to_huge(n,h1);
	return h2=h1-h;
}


//------------------前置运算  --HugeInt ---------------------//
HugeInt HugeInt::operator--(){
	HugeInt result;
	result=*this-1L;
	return (*this=result);
}

//------------------后置运算 HugeInt--    ------------------//
HugeInt HugeInt::operator--(int nouse){
	HugeInt result,temp;
	temp=*this;
	result=*this-1L;
	*this=result;
	return temp;
}

HugeInt HugeInt::operator-=(const HugeInt &h){
	
	*this=*this-h;
	return *this;
}