大整数类c++实现

// bigint.cpp: implementation of the bigint class. //定义一个超高精度的类bigint的实现算法代码，用以实现超过20位有效数字整型数值 //的运算，并具有兼容已有整型数据int的能力，能与int数据混合运算。 ////////////////////////////////////////////////////////////////////// #include<string.h> #include "bigint.h" #include <stdlib.h> #include <math.h> #define z1 "0" #define z2 "00" #define z3 "000" #define z4 "0000" #define R 10000 ////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////// //空初始化 bigint::bigint() { sign=1; arr_n=1; sl=new long[arr_n]; sl[0] =0; soure=new char[8]; soure="0"; } //把数值字符串设置值给bigint类对象 void bigint::setval(const char * s) { char SIGN,temp[5]; int len,i,j=4,k=0; SIGN=s[0]; switch(SIGN) { case '-': case '+': { if(SIGN=='-')sign=-1; //判断正负 if(SIGN=='+')sign=+1; len=strlen(s); //把数值字符串保存到soure中，包括'\0'和符号位 soure=new char[len+1]; strcpy(soure,s); for(int n=0;n<=len;n++)soure[n]=soure[n+1]; //去掉符号位 len=strlen(soure); if (len%4==0) arr_n=(int)len/4; else arr_n=(int)(len/4+1); sl=new long[arr_n]; for(i=len;i>=0;i--) //把数值串赋值给数组，每四个数值字符转换成一个长整数 { temp[j]=soure[i]; if(i==0&&j) for(int q=0;q<j;q++)temp[q]='0'; if(j==0||i==0) { temp[4]='\0'; sl[k]=atol(temp); j=4;k++; } j--; } break; } default: { sign=+1; len=strlen(s); soure=new char[len+1]; strcpy(soure,s); if (len%4==0) arr_n=(int)len/4; else arr_n=(int)(len/4+1); sl=new long[arr_n]; for(i=len;i>=0;i--) //把数值串赋值给数组 { temp[j]=soure[i]; if(i==0&&j) for(int q=0;q<j;q++)temp[q]='0'; if(j==0||i==0) { temp[4]='\0'; sl[k]=atol(temp); j=4;k++; } j--; } break; } } } //拷贝构造函数 bigint::bigint(const bigint & a) { int i; sign=a.sign; int n=strlen(a.soure); soure=new char[n+1]; for(i=0;i<=n;i++) soure[i]=a.soure[i]; arr_n=a.arr_n; sl=new long[arr_n]; for(i=0; i<arr_n; i++) sl[i]=a.sl[i]; } //获取值,以字符串方式取出 char * bigint::getval () { char * temp,*e="-"; if(sign==-1) { temp=new char[strlen(soure)+2]; strcpy(temp,e); strcat(temp,soure); } else { temp=new char[strlen(soure)+1]; strcpy(temp,soure); } return temp; } //以数值字符串进行初始化 bigint::bigint(const char * s) { setval(s); } //大于比较：真值为ture；假值为flase bool bigint::operator >(const bigint &num) { if(sign >num.sign ) return true; if (sign==1&&num.sign==1) { if (strlen(soure) >strlen(num.soure) ) return true; if ((strlen(soure) ==strlen(num.soure))&&(strcmp(soure ,num.soure )>0)) return true; } if (sign==-1&&num.sign==-1) { if (strlen(soure) <strlen(num.soure) ) return true; if ((strlen(soure) ==strlen(num.soure))&&(strcmp(soure ,num.soure )<0)) return true; } return false; } //等于比较：真值为ture；假值为flase bool bigint::operator ==(const bigint &num) { if ((sign==num.sign)&&(strcmp(soure ,num.soure )==0)) return true; else return false; } //不等于比较：真值为ture；假值为flase bool bigint::operator !=(const bigint &num) { if ((sign!=num.sign)||(strcmp(soure ,num.soure )!=0)) return true; else return false; } //大于等于比较：真值为ture；假值为flase bool bigint::operator >=(const bigint &num) { if(*this>num||*this==num)return true; else return false; } //小于比较：真值为ture；假值为flase bool bigint::operator <(const bigint &num) { if(!(*this>=num))return true; else return false; } //小于等于比较：真值为ture；假值为flase bool bigint::operator <=(const bigint &num) { if(!(*this>num)) return true; else return false; } //进位、借位调整器 void regulator(bigint *num) { int i; for(i=0;i<num->arr_n ;i++) { if(num->sl[i]>=R) //进位调整 { num->sl[i+1]+=num->sl[i]/R; num->sl[i]%=R; } if(num->sl[i]<0) //借位调整 { num->sl[i+1]=num->sl[i+1]-1; num->sl[i]+=R; } } } void regulator_sign(bigint *num) //符号调整 { int flag=1,i; if(num->sl[num->arr_n-1]<0)flag=-1; num->sign=flag*num->sign; for(i=0;i<num->arr_n ;i++)num->sl[i]=flag*num->sl[i]; } //整理数组值到串soure void sltostr(bigint *num) { int i; char * n_temp,*c_temp; n_temp=new char[5]; c_temp=new char[5]; num->soure =new char[num->arr_n *4+4]; //为什么要再加上4？ num->soure[0]='\0'; i=num->arr_n-1; if(num->sl[i]) //处理最高位 { ltoa(num->sl[i],n_temp,10) ; strcpy(num->soure ,n_temp); } int l=0; while(i) //处理高位后的各位数 { i--; ltoa(num->sl[i],n_temp,10); l=4-strlen(n_temp); if(l>0) { if(l==1)strcpy(c_temp,z1); if(l==2)strcpy(c_temp,z2); if(l==3)strcpy(c_temp,z3); if(l==4)strcpy(c_temp,z4); strcat(num->soure,c_temp); } strcat(num->soure,n_temp); } int len; while(num->soure[0]=='0')//去除无效0的处理 { len=strlen(num->soure ); for(i=0;i<len; i++) num->soure [i]=num->soure [i+1]; } if(num->soure[0]=='\0')strcpy(num->soure,"0"); } //与常规整数的加运算 bigint bigint::operator +(int num) { char * s; s=new char[strlen(getval())+1]; strcpy(s,getval()); bigint temp(s); char * ss; ss=new char[31]; itoa(num,ss,10); bigint AA(ss); bigint temp0; temp0=temp+AA; return temp0; } //与常规整数的减运算 bigint bigint::operator -(int num) { char * s; s=new char[strlen(getval())+1]; strcpy(s,getval()); bigint temp(s); //取左操作数 char * ss; ss=new char[31]; itoa(num,ss,10); bigint A(ss); //取右操作数 bigint temp0; temp0=temp-A; return temp0; } //加运算 bigint bigint::operator +(const bigint &num) { int i; bigint temp; temp.arr_n =arr_n>num.arr_n ?arr_n:num.arr_n ; if((arr_n==num.arr_n )&&abs((sl[arr_n-1]*sign+num.sl[num.arr_n-1 ]*num.sign ))>=R) ++temp.arr_n ; temp.sl=new long[temp.arr_n ]; for(i=0;i<temp.arr_n ;i++)temp.sl[i]=0; for(i=0;i<temp.arr_n ;i++) { if((i>=arr_n)&&(num.arr_n>arr_n ))temp.sl[i]=num.sl[i]*num.sign ; if((i>=num.arr_n )&&(arr_n >num.arr_n))temp.sl[i]=sl[i]*sign; if((i<arr_n)&&(i< num.arr_n ))temp.sl[i]=sl[i]*sign+num.sl[i]*num.sign ; } regulator_sign(&temp); //必须先做符号调整让temp中sl的最高位符号为正，再进位、借位调整 regulator(&temp); //进位借位调整完后sl中的数都是正数了 sltostr(&temp); return temp; } //求相反数 bigint bigint:: operator -() { char * s; s=new char[strlen(getval())+1]; strcpy(s,getval()); bigint temp(s); temp.sign *=-1; return temp; } //减运算 bigint bigint::operator -(const bigint &num) { bigint temp,A; A=num ; A.sign *=-1 ; temp=*this+A; return temp; } //与常规整数的乘运算 bigint bigint::operator *(int num) { int i,j; char * ss; ss=new char [31]; itoa(num ,ss,10); bigint temp,a(ss); temp.arr_n =arr_n+a.arr_n ; temp.sign =sign*a.sign ; temp.sl=new long[temp.arr_n ]; for(i=0;i<temp.arr_n ;i++)temp.sl[i]=0; for(i=0;i<arr_n;i++) { for(j=0;j<a.arr_n ;j++) { temp.sl[i+j]+=sl[i]*a.sl[j]; } regulator(&temp); } sltostr(&temp); return temp; } //乘运算 bigint bigint::operator *(const bigint &num) { int i,j; bigint temp; temp.sign =sign*num.sign ; temp.arr_n =arr_n+num.arr_n ; temp.sl=new long[temp.arr_n ]; for(i=0;i<temp.arr_n ;i++)temp.sl[i]=0; for(i=0;i<arr_n;i++) { for(j=0;j<num.arr_n ;j++) { temp.sl[i+j]+=sl[i]*num.sl[j]; } regulator(&temp); //此处不用符号调整，因为加数与被加数sl中对应各位都是正数 }