c++大数模板

#include<iostream>

#include<cstring>

#include<iomanip>

#include<algorithm>

#include<cstdlib>

#include<cstdio>

using namespace std;



#define MAXN 9999

#define MAXSIZE 1000

#define DLEN 4



class BigNum

{

private:

    int a[MAXSIZE];    //可以控制大数的位数

    int len;       //大数长度

public:

    BigNum(){ len = 1;memset(a,0,sizeof(a)); }   //构造函数

    BigNum(const int);       //将一个int类型的变量转化为大数

    BigNum(const char*);     //将一个字符串类型的变量转化为大数

    BigNum(const BigNum &);  //拷贝构造函数

    BigNum &operator=(const BigNum &);   //重载赋值运算符,大数之间进行赋值运算



    friend istream& operator>>(istream&,  BigNum&);   //重载输入运算符

    friend ostream& operator<<(ostream&,  BigNum&);   //重载输出运算符



    BigNum operator+(const BigNum &) const;   //重载加法运算符,两个大数之间的相加运算

    BigNum operator-(const BigNum &) const;   //重载减法运算符,两个大数之间的相减运算

    BigNum operator*(const BigNum &) const;   //重载乘法运算符,两个大数之间的相乘运算

    BigNum operator/(const int   &) const;    //重载除法运算符,大数对一个整数进行相除运算



    BigNum operator^(const int  &) const;    //大数的n次方运算

    int    operator%(const int  &) const;    //大数对一个int类型的变量进行取模运算

    bool   operator>(const BigNum & T)const;   //大数和另一个大数的大小比较

    bool   operator>(const int & t)const;      //大数和一个int类型的变量的大小比较



    void print();       //输出大数

};

BigNum::BigNum(const int b)     //将一个int类型的变量转化为大数

{

    int c,d = b;

    len = 0;

    memset(a,0,sizeof(a));

    while(d > MAXN)

    {

        c = d - (d / (MAXN + 1)) * (MAXN + 1);

        d = d / (MAXN + 1);

        a[len++] = c;

    }

    a[len++] = d;

}

BigNum::BigNum(const char*s)     //将一个字符串类型的变量转化为大数

{

    int t,k,index,l,i;

    memset(a,0,sizeof(a));

    l=strlen(s);

    len=l/DLEN;

    if(l%DLEN)

        len++;

    index=0;

    for(i=l-1;i>=0;i-=DLEN)

    {

        t=0;

        k=i-DLEN+1;

        if(k<0)

            k=0;

        for(int j=k;j<=i;j++)

            t=t*10+s[j]-'0';

        a[index++]=t;

    }

}

BigNum::BigNum(const BigNum & T) : len(T.len)  //拷贝构造函数

{

    int i;

    memset(a,0,sizeof(a));

    for(i = 0 ; i < len ; i++)

        a[i] = T.a[i];

}

BigNum & BigNum::operator=(const BigNum & n)   //重载赋值运算符,大数之间进行赋值运算

{

    int i;

    len = n.len;

    memset(a,0,sizeof(a));

    for(i = 0 ; i < len ; i++)

        a[i] = n.a[i];

    return *this;

}

istream& operator>>(istream & in,  BigNum & b)   //重载输入运算符

{

    char ch[MAXSIZE*4];

    int i = -1;

    in>>ch;

    int l=strlen(ch);

    int count=0,sum=0;

    for(i=l-1;i>=0;)

    {

        sum = 0;

        int t=1;

        for(int j=0;j<4&&i>=0;j++,i--,t*=10)

        {

            sum+=(ch[i]-'0')*t;

        }

        b.a[count]=sum;

        count++;

    }

    b.len =count++;

    return in;



}

/*ostream& operator<<(ostream& out,  BigNum& b)   //重载输出运算符

{

    int i;

    cout << b.a[b.len - 1];

    for(i = b.len - 2 ; i >= 0 ; i--)

    {

        cout.width(DLEN);

        cout.fill('0');

        cout << b.a[i];

    }

    return out;

}*/



BigNum BigNum::operator+(const BigNum & T) const   //两个大数之间的相加运算

{

    BigNum t(*this);

    int i,big;      //位数

    big = T.len > len ? T.len : len;

    for(i = 0 ; i < big ; i++)

    {

        t.a[i] +=T.a[i];

        if(t.a[i] > MAXN)

        {

            t.a[i + 1]++;

            t.a[i] -=MAXN+1;

        }

    }

    if(t.a[big] != 0)

        t.len = big + 1;

    else

        t.len = big;

    return t;

}

BigNum BigNum::operator-(const BigNum & T) const   //两个大数之间的相减运算

{

    int i,j,big;

    bool flag;

    BigNum t1,t2;

    if(*this>T)

    {

        t1=*this;

        t2=T;

        flag=0;

    }

    else

    {

        t1=T;

        t2=*this;

        flag=1;

    }

    big=t1.len;

    for(i = 0 ; i < big ; i++)

    {

        if(t1.a[i] < t2.a[i])

        {

            j = i + 1;

            while(t1.a[j] == 0)

                j++;

            t1.a[j--]--;

            while(j > i)

                t1.a[j--] += MAXN;

            t1.a[i] += MAXN + 1 - t2.a[i];

        }

        else

            t1.a[i] -= t2.a[i];

    }

    t1.len = big;

    while(t1.a[len - 1] == 0 && t1.len > 1)

    {

        t1.len--;

        big--;

    }

    if(flag)

        t1.a[big-1]=0-t1.a[big-1];

    return t1;

}



BigNum BigNum::operator*(const BigNum & T) const   //两个大数之间的相乘运算

{

    BigNum ret;

    int i,j,up;

    int temp,temp1;

    for(i = 0 ; i < len ; i++)

    {

        up = 0;

        for(j = 0 ; j < T.len ; j++)

        {

            temp = a[i] * T.a[j] + ret.a[i + j] + up;

            if(temp > MAXN)

            {

                temp1 = temp - temp / (MAXN + 1) * (MAXN + 1);

                up = temp / (MAXN + 1);

                ret.a[i + j] = temp1;

            }

            else

            {

                up = 0;

                ret.a[i + j] = temp;

            }

        }

        if(up != 0)

            ret.a[i + j] = up;

    }

    ret.len = i + j;

    while(ret.a[ret.len - 1] == 0 && ret.len > 1)

        ret.len--;

    return ret;

}

BigNum BigNum::operator/(const int & b) const   //大数对一个整数进行相除运算

{

    BigNum ret;

    int i,down = 0;

    for(i = len - 1 ; i >= 0 ; i--)

    {

        ret.a[i] = (a[i] + down * (MAXN + 1)) / b;

        down = a[i] + down * (MAXN + 1) - ret.a[i] * b;

    }

    ret.len = len;

    while(ret.a[ret.len - 1] == 0 && ret.len > 1)

        ret.len--;

    return ret;

}

int BigNum::operator %(const int & b) const    //大数对一个int类型的变量进行取模运算

{

    int i,d=0;

    for (i = len-1; i>=0; i--)

    {

        d = ((d * (MAXN+1))% b + a[i])% b;

    }

    return d;

}

BigNum BigNum::operator^(const int & n) const    //大数的n次方运算

{

    BigNum t,ret(1);

    int i;

    if(n<0)

        exit(-1);

    if(n==0)

        return 1;

    if(n==1)

        return *this;

    int m=n;

    while(m>1)

    {

        t=*this;

        for( i=1;i<<1<=m;i<<=1)

        {

            t=t*t;

        }

        m-=i;

        ret=ret*t;

        if(m==1)

            ret=ret*(*this);

    }

    return ret;

}

bool BigNum::operator>(const BigNum & T) const   //大数和另一个大数的大小比较

{

    int ln;

    if(len > T.len)

        return true;

    else if(len == T.len)

    {

        ln = len - 1;

        while(a[ln] == T.a[ln] && ln >= 0)

            ln--;

        if(ln >= 0 && a[ln] > T.a[ln])

            return true;

        else

            return false;

    }

    else

        return false;

}

bool BigNum::operator >(const int & t) const    //大数和一个int类型的变量的大小比较

{

    BigNum b(t);

    return *this>b;

}



void BigNum::print()    //输出大数

{

    int i;

    //cout << a[len - 1];

    printf("%d",a[len-1]);

    for(i = len - 2 ; i >= 0 ; i--)

    {

        /*cout.width(DLEN);

        cout.fill('0');

        cout << a[i];*/

        printf("%04d",a[i]);

    }

    //cout << endl;

    printf("\n");

}

int main(void)

{

    int i,n,ttt=1;



    char s[100];

    int text;

    //scanf("%d",&text);

    cin>>text;

    while(text--)

    {

        scanf("%s",s);

        BigNum x(s),z;

        z=x*x*8-x*7+1;

        printf("Case #%d: ",ttt++);

        z.print();

    }

    return 0;

}

  

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