1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
#include <iostream>
#include <string>
using namespace std;
class BigInt
{
friend BigInt operator+(const BigInt& num1, const BigInt& num2);
friend ostream& operator<<(ostream& os, const BigInt& num);
friend bool AddBigInt(const BigInt& Num1, const BigInt& Num2, BigInt& Sum);
friend bool AddWithLongestFirst(const BigInt& longer, const BigInt& shorter, BigInt& sum );
public:
static const int MAX_DIGITS = 5; // "nested" and "public" instead of "Global"
BigInt(); // set numDigits to 0 -- this means the BigInt is 0
BigInt(const string& goodString); // assume "goodString" is perfect - no blanks or non-digits
bool ReadBigInt(istream& is); // default stream arg; ReadBigInt() means use "cin"
void PrintBigInt( ostream& os) const;
bool StringToBigInt(const string& goodString, const BigInt& num);
// ExtractGoodString is "optional"
//bool ExtractGoodString( const string& input, string& output);
private:
int Digits[MAX_DIGITS];
int numDigit;
};
BigInt::BigInt():numDigit(0)
{
}
BigInt::BigInt(const string& goodString)
{
numDigit=goodString.length();
if(numDigit>BigInt::MAX_DIGITS)
return false;
int j=0;
for(int i=numDigit-1;i>=0;i--)
{
Digits[j]=goodString[i]-'0';
j++;
}
}
bool BigInt::ReadBigInt(istream& is)
{
string goodString;
BigInt num;
is>>goodString;
StringToBigInt(goodString,num);
return true;
}
bool StringToBigInt(const string& goodString, BigInt& num)
{
numDigit=goodString.length();
if(numDigit>BigInt::MAX_DIGITS)
return false;
int j=0;
for(int i=numDigit-1;i>=0;i--)
{
Digits[j]=goodString[i]-'0';
j++;
}
}
void BigInt::PrintBigInt(ostream& os) const
{
for(int i=numDigit-1;i>=0;i--)
os<<Digits[i];
os<<endl;
}
bool AddBigInt(const BigInt& num1, const BigInt& num2, BigInt& sum)
{
if(num1.numDigit>num2.numDigit)
return AddWithLongestFirst(num1,num2,sum);
else
return AddWithLongestFirst(num2,num1,sum);
}
bool AddWithLongestFirst(const BigInt& Long, const BigInt& Short, BigInt& Sum)
{
int carry=0;
int temp;
for(int i=0; i<Short.numDigit; i++)
{
temp=Long.Digits[i]+Short.Digits[i]+carry;
if(temp>=10)
{
Sum.Digits[i]= temp-10;
carry=1;
}
else
{
carry=0;
Sum.Digits[i]=temp;
}
}
for(int j=Short.numDigit; j<Long.numDigit; j++)
{
temp=Long.Digits[j]+carry;
if(temp>=10)
{
Sum.Digits[j]=temp-10;
carry=1;
}
else
{
Sum.Digits[j]=temp;
carry=0;
}
}
if(carry==1 && Long.numDigit < BigInt::MAX_DIGITS)
{
Sum.Digits[Long.numDigit]=1;
Sum.numDigit=Long.numDigit+1;
return true;
}
else if(Long.numDigit <= BigInt::MAX_DIGITS && carry==0)
{
Sum.numDigit=Long.numDigit;
return true;
}
else
return false;
}
BigInt operator +(const BigInt& num1, const BigInt& num2)
{
BigInt Sum;
if(AddBigInt(num1,num2,Sum))
return Sum;
else
return 0;
}
void main()
{
}
|
