c++打卡第三十一天
一、问题描述
设计并实现大数类BigNum
二、描述
定义一个整数型大数类，要求能够完成100位以内的较大整数的加法和减法计算，main(void)函数完成对其的测试。、
BigNum类结构说明：
BigNum类的数据成员包括： ①私有数据成员：数值域num(char []型)。 BigNum类成员函数包括： ①有参构造函数BigNum(char c[])和拷贝构造函数BigNum(const BigNum &)，其中有参构造函数参数默认值为"+0"，输出信息"BigNum Constructor run"，拷贝构造函数输出信息"BigNum CopyConstructor run" ②析构函数，析构函数输出信息"BigNum Destructor run" ③公有函数成员void setNum(char c[])和char const *getNum(void) const分别返回和设置数值域。 ④重载“+”运算符，实现两个BigNum对象相加的运算 ⑤重载“-”运算符，实现两个BigNum对象相减的运算 ⑥公有成员函数void show() const用于显示BigNum对象的信息，显示格式为：BigNum(<数值域>)
建议：大数存储时专门存储符号位且低位存储在前，高位存储在后。这样便于运算实现。
裁判测试程序样例：
#include <iostream> using namespace std; #define N 100 /*请在这里填写答案*/ //主函数 int main(void){ char c[100],op; cin>>c; BigNum b1(c),b2(b1); b1.show(); cin>>c; b2.setNum(c); b2.show(); cin>>op; if(op=='+') (b1+b2).show(); if(op=='-') (b1-b2).show(); return 0; }
输入样例：
123
234
-
输出样例：
BigNum Constructor run BigNum CopyConstructor run BigNum(+123) BigNum(+234) BigNum Constructor run BigNum CopyConstructor run BigNum Destructor run BigNum(-111) BigNum Destructor run BigNum Destructor run BigNum Destructor run
三、代码实现
#include<cstring> class BigNum { private: char num[N]; public: BigNum( char c[N] = "+0" ); BigNum( const BigNum &p ); ~BigNum() { cout<<"BigNum Destructor run"<<endl; } void setNum( char c[N] ); char const * getNum(void) const; BigNum operator + ( const BigNum &a ); BigNum operator - ( BigNum &b ); void show() const; }; BigNum::BigNum( char c[N] ) { int i,j,a = strlen(c); if( c[0] != '-') { num[0] = '+'; if( c ) { for( i=strlen(c), j=0; i>=1; i--,j++) { num[i] = c[j]; } } num[a+1] = '\0'; } else { num[0] = c[0]; for( i=strlen(c)-1, j=1; i>=1; i--,j++) { num[i] = c[j]; } num[a] = '\0'; } cout<<"BigNum Constructor run"<<endl; } BigNum::BigNum( const BigNum &p ) { int i=0; if(p.num) { while( p.num[i] != '\0' ) { num[i] = p.num[i]; i++; } num[i] = '\0'; } cout<<"BigNum CopyConstructor run"<<endl; } void BigNum::setNum( char c[N] ) { int i,j,a = strlen(c); if( c[0] != '-') { num[0] = '+'; if( c ) { for( i=strlen(c), j=0; i>=1; i--,j++) { num[i] = c[j]; } } num[a+1] = '\0'; } else { num[0] = c[0]; for( i=strlen(c)-1, j=1; i>=1; i--,j++) { num[i] = c[j]; } num[a] = '\0'; } } char const * BigNum::getNum(void) const { return num; } BigNum BigNum::operator + ( const BigNum &a ) { if(num[0]=='+' && a.num[0]=='-') { BigNum s2(a); s2.num[0] = '+'; return (*this) - s2; } if(num[0]=='-' && a.num[0]=='+') { BigNum s2(a); num[0] = '+'; return s2 - (*this); } BigNum s; int i; char s2[N]; for( i=0; a.num[i]!='\0'; i++) { s2[i] = a.num[i]; } s2[i] = '\0'; int len1 = strlen(num); int len2 = strlen(s2); int Max=0; if( len1 > len2) { Max = len1; num[len1] = '0'; for( i=len2; i<=len1; i++) { s2[i] = '0'; } } else { if( len1 < len2 ) { Max = len2; s2[len2] = '0'; for( i=len1; i<=len2; i++) { num[i] = '0'; } } else { Max = len1; s2[len2] = '0'; num[len1] = '0'; } } if( (num[0]=='+' && s2[0]=='+') || (num[0]=='-' && s2[0]=='-') ) { for( i=1; i<=Max; i++) { int c = ( (num[i]-'0') + (s2[i]-'0') ); if( c>= 10 ) { c -= 10; s.num[i] = char( c +'0'); s2[i+1]++; } else { s.num[i] = char( c + '0'); } } s.num[i] = '\0'; if(num[0]=='+' && s2[0]=='+') { s.num[0] = '+'; } if(num[0]=='-' && s2[0]=='-' ) { s.num[0] = '-'; } } return s; } BigNum BigNum::operator - ( BigNum &b ) { if(num[0]=='+' && b.num[0]=='-') { BigNum s2(b); s2.num[0] = '+'; return (*this) + s2; } if(num[0]=='-' && b.num[0]=='+') { BigNum s2(b); s2.num[0] = '-'; return (*this) + s2; } BigNum s; int i; char s2[N]; for( i=0; b.num[i]!='\0'; i++) { s2[i] = b.num[i]; } s2[i] = '\0'; int len1 = strlen(num); int len2 = strlen(s2); int Max=0; if( len1 > len2) { Max = len1; num[len1] = '0'; for( i=len2; i<=len1; i++) { s2[i] = '0'; } } else { if( len1 < len2 ) { Max = len2; s2[len2] = '0'; for( i=len1; i<=len2; i++) { num[i] = '0'; } } else { Max = len1; s2[len2] = '0'; num[len1] = '0'; } } if( (num[0]=='+' && s2[0]=='+') || (num[0]=='-' && s2[0]=='-') ) { if(num[0]=='-' && s2[0]=='-') { s2[0] = '+'; num[0] = '+'; for( i=0; num[i]!='\0'; i++ ) { char ch; ch = num[i]; num[i] = s2[i]; s2[i] = ch; } } char s1[N]; char s3[N]; int j; for( i=Max,j=0; i>0; j++,i--) { s1[j] = num[i]; } s1[j] = '\0'; for( i=Max,j=0; i>0; j++,i--) { s3[j] = s2[i]; } s3[j] = '\0'; if( strcmp(s1,s3)>0 ) { s.num[0] = '+'; for( i=1; i<=Max; i++) { int c = ( (num[i]-'0') - (s2[i]-'0')); if( c<0 ) { c+=10; s.num[i] = char( c + '0'); num[i+1]--; } else { s.num[i] = char( c + '0'); } } s.num[i] = '\0'; } else { if( strcmp(s1,s3)<0 ) { s.num[0] = '-'; for( i=1; i<=Max; i++) { int c = ( (s2[i]-'0') - (num[i]-'0')); if( c<0 ) { c+=10; s.num[i] = char( c + '0'); s2[i+1]--; } else { s.num[i] = char( c + '0'); } } s.num[i] = '\0'; } else { s.num[0] = '+'; s.num[1] = '0'; s.num[2] = '\0'; } } } return s; } void BigNum::show() const { char ch[N] = "+0"; char c[N] = "+00"; //cout<<num<<endl; if( strcmp(ch,num) == 0 || strcmp(c,num) == 0 ) { cout<<"BigNum("<<ch<<")"<<endl; } else { cout<<"BigNum("<<num[0]; int i; int flag; for( i=strlen(num)-1; i>=0; i--) { if(num[i]!='0') { flag = i; break; } } for( i=flag; i>=1; i--) { cout<<num[i]; } cout<<")"<<endl; } }
