电子协会编程C语言指导教师培训——实数加法

1. #include <iostream>
2. #include <cstdio>
3. #include <string.h>
4. using namespace std;
5. #define N 105
6. char a[N],b[N];
7. int a1[N]={0},a2[N]={0};
8. int b1[N]={0},b2[N]={0};
9. int fj(char a[],int a1[],int a2[])
10. {
11.   int len=0;
12.   while(a[len]!='.')len++;
13.   int i,j;
14.   for(i=1,j=len-1;j>=0;i++,j--){
15.     a1[i]=a[j]-'0';
16.   }
17.   int lenl=strlen(a);
18.   for(i=1,j=len+1;j<lenl;i++,j++){
19.     a2[i]=a[j]-'0';
20.   }
21.   return len;
22. }
23. int xjia1(int a[],int b[],int len1,int len2)
24. {
25.   int i=1,jw=0;
26.   int lenll=max(len1,len2);
27.   while(i<=lenll){
28.     a[i]+=b[i]+jw;
29.     if(a[i]>=10){
30.       jw=1;
31.       a[i]%=10;
32.     }
33.     else jw=0;
34.     i++;  
35.   }
36.   if(jw>0){
37.     a[i]+=1;
38.     lenll++;
39.   }
40.   return lenll;
41. }
42. int xjia2(int a[],int b[],int len1,int len2)
43. {
44.   int jw=0;
45.   int i=max(len1,len2); 
46.   while(i>=1){
47.     a[i]+=b[i]+jw;
48.     if(a[i]>=10){
49.       jw=1;
50.       a[i]%=10;
51.     }
52.     else jw=0;
53.     i--;  
54.   }
55.   if(jw>0){
56.     a[i]+=1;
57.   }
58.   return max(len1,len2);
59. }
60. int main(int argc, char *argv[])
61. {
62.   cin>>a>>b;
63.   int lena1=fj(a,a1,a2);
64.   int lena2=strlen(a)-lena1-1;
65.   int lenb1=fj(b,b1,b2);
66.   int lenb2=strlen(b)-lenb1-1;
67. 
68.   int len1=xjia1(a1,b1,lena1,lenb1);
69.   int len2=xjia2(a2,b2,lena2,lenb2);
70.   if(a2[0]>0)a1[1]+=1;
71.   for(int i=len1;i>=1;i--)cout<<a1[i];
72.   cout<<".";
73.   while(a2[len2]==0)len2--;
74.   for(int i=1;i<=len2;i++)cout<<a2[i];
75.   cout<<endl;
76.   return 0;
77. }

1. //纯面向对象实现
2. #include <iostream>
3. #include <algorithm>
4. #include <string>
5. using namespace std;
6. class RealNumber
7. {
8. public:
9.  RealNumber():m_number(""),m_left(""),m_right(""){}
10.   RealNumber(const char* data)
11.   {
12.     m_number=data;
13.     int pos = m_number.find_first_of(".");
14.     if(pos>=0)
15.     {
16.       m_left = m_number.substr(0,pos);
17.       m_right=m_number.substr(pos+1);
18.     }
19.     else
20.       m_left =m_number;
21.   }
22. 
23.   RealNumber& operator =(const char* data)
24.   {
25.     RealNumber t(data);
26.     *this = t;
27.     return *this;
28.   }
29. 
30.   RealNumber operator +(const RealNumber &num)
31.   {
32.     RealNumber a=*this,b=num,c;
33.     add_left(a.m_left,b.m_left,c.m_left);
34.     int p=add_right(a.m_right,b.m_right,c.m_right);
35.     if(p)
36.       add_left(c.m_left,string(1,'0'+p),c.m_left);
37.     if(c.m_right.length())
38.       c.m_number = c.m_left +"."+c.m_right;
39.     else
40.       c.m_number = c.m_left;
41.     return c;
42.   }
43. 
44.   friend ostream& operator <<(ostream &os,const RealNumber &num)
45.   {
46.     os<<num.m_number;
47.     return os;
48.   }
49.   friend istream& operator >>(istream &is,RealNumber &num)
50.   {
51.     string t;
52.     is>>t;
53.     num=t.c_str();
54.     return is;
55.   }
56. private:
57.   int add_right(string a,string b,string &c)
58.   {
59.     //补齐长度 
60.     if(a.length()>b.length())
61.       b.append(a.length()-b.length(),'0');
62.     else if(a.length()<b.length())
63.       a.append(b.length()-a.length(),'0');
64.     c = string(a.length(),'0');
65.     //逆序
66.     reverse(a.begin(),a.end());
67.     reverse(b.begin(),b.end());
68.     int i,p=0;
69.     for(i=0;i<a.length();i++)
70.     {
71.       c[i]=p+a[i]+b[i]-'0';
72.       p=0;
73.       if(c[i]>'9')
74.       {
75.         c[i]-=10;
76.         p=1;
77.       }
78.     } 
79.     //去掉0
80.     while(c.length())
81.     {
82.       if(*c.begin()=='0')
83.         c.erase(c.begin());
84.       else
85.         break;
86.     }
87.     //结果逆序
88.     reverse(c.begin(),c.end());
89.     return p;
90.   } 
91.   void add_left(string a,string b,string &c)
92.   {
93.     //逆序
94.     reverse(a.begin(),a.end());
95.     reverse(b.begin(),b.end());
96.     //补齐长度 
97.     if(a.length()>b.length())
98.       b.append(a.length()-b.length(),'0');
99.     else if(a.length()<b.length())
100.      a.append(b.length()-a.length(),'0');
101.    c = string(a.length(),'0');
102.    int p=0;
103.    for(int i=0;i<a.length();i++)
104.    {
105.      c[i]=p+a[i]+b[i]-'0';
106.      p=0;
107.      if(c[i]>'9')
108.      {
109.        c[i]-=10;
110.        p=1;
111.      }
112.    } 
113.    if(p)
114.      c.append(1,'0'+p);
115.    //结果逆序
116.    reverse(c.begin(),c.end());
117.  }
118. private:
119.  string m_number;
120.  string m_left;
121.  string m_right;
122. };
123. 
124. using namespace std;
125. int main(int argc, char *argv[])
126. {
127.  RealNumber r1,r2;
128.  cin>>r1>>r2;
129.  cout<<(r1+r2)<<endl;
130.  return 0;
131. }