C++ BigInteger模板
1 #include <cstdio> 2 #include <cstring> 3 #include <string> 4 #include <iostream> 5 #include <iomanip> 6 #include <algorithm> 7 using namespace std; 8 9 #define MAXN 9999 10 #define MAXSIZE 10 11 #define DLEN 4 12 const long long MOD = 258280327; 13 class BigInteger 14 { 15 private: 16 int a[3000]; //可以控制大数的位数 17 int len; //大数长度 18 public: 19 BigInteger(){ len = 1; memset(a, 0, sizeof(a)); } //构造函数 20 BigInteger(const int); //将一个int类型的变量转化为大数 21 BigInteger(const char*); //将一个字符串类型的变量转化为大数 22 BigInteger(const BigInteger &); //拷贝构造函数 23 BigInteger &operator=(const BigInteger &); //重载赋值运算符，大数之间进行赋值运算 24 25 friend istream& operator>>(istream&, BigInteger&); //重载输入运算符 26 friend ostream& operator<<(ostream&, BigInteger&); //重载输出运算符 27 28 BigInteger operator+(const BigInteger &) const; //重载加法运算符，两个大数之间的相加运算 29 BigInteger operator-(const BigInteger &) const; //重载减法运算符，两个大数之间的相减运算 30 BigInteger operator*(const BigInteger &) const; //重载乘法运算符，两个大数之间的相乘运算 31 BigInteger operator/(const int &) const; //重载除法运算符，大数对一个整数进行相除运算 32 33 BigInteger operator^(const int &) const; //大数的n次方运算 34 long long operator%(const long long &) const; //大数对一个int类型的变量进行取模运算 35 bool operator>(const BigInteger & T)const; //大数和另一个大数的大小比较 36 bool operator>(const int & t)const; //大数和一个int类型的变量的大小比较 37 38 void print(); //输出大数 39 }; 40 BigInteger::BigInteger(const int b) //将一个int类型的变量转化为大数 41 { 42 int c, d = b; 43 len = 0; 44 memset(a, 0, sizeof(a)); 45 while (d > MAXN) 46 { 47 c = d - (d / (MAXN + 1)) * (MAXN + 1); 48 d = d / (MAXN + 1); 49 a[len++] = c; 50 } 51 a[len++] = d; 52 } 53 BigInteger::BigInteger(const char*s) //将一个字符串类型的变量转化为大数 54 { 55 int t, k, index, l, i; 56 memset(a, 0, sizeof(a)); 57 l = strlen(s); 58 len = l / DLEN; 59 if (l%DLEN) 60 len++; 61 index = 0; 62 for (i = l - 1; i >= 0; i -= DLEN) 63 { 64 t = 0; 65 k = i - DLEN + 1; 66 if (k<0) 67 k = 0; 68 for (int j = k; j <= i; j++) 69 t = t * 10 + s[j] - '0'; 70 a[index++] = t; 71 } 72 } 73 BigInteger::BigInteger(const BigInteger & T) : len(T.len) //拷贝构造函数 74 { 75 int i; 76 memset(a, 0, sizeof(a)); 77 for (i = 0; i < len; i++) 78 a[i] = T.a[i]; 79 } 80 BigInteger & BigInteger::operator=(const BigInteger & n) //重载赋值运算符，大数之间进行赋值运算 81 { 82 int i; 83 len = n.len; 84 memset(a, 0, sizeof(a)); 85 for (i = 0; i < len; i++) 86 a[i] = n.a[i]; 87 return *this; 88 } 89 istream& operator>>(istream & in, BigInteger & b) //重载输入运算符 90 { 91 char ch[MAXSIZE * 4]; 92 int i = -1; 93 in >> ch; 94 int l = strlen(ch); 95 int count = 0, sum = 0; 96 for (i = l - 1; i >= 0;) 97 { 98 sum = 0; 99 int t = 1; 100 for (int j = 0; j<4 && i >= 0; j++, i--, t *= 10) 101 { 102 sum += (ch[i] - '0')*t; 103 } 104 b.a[count] = sum; 105 count++; 106 } 107 b.len = count++; 108 return in; 109 110 } 111 ostream& operator<<(ostream& out, BigInteger& b) //重载输出运算符 112 { 113 int i; 114 cout << b.a[b.len - 1]; 115 for (i = b.len - 2; i >= 0; i--) 116 { 117 cout.width(DLEN); 118 cout.fill('0'); 119 cout << b.a[i]; 120 } 121 return out; 122 } 123 124 BigInteger BigInteger::operator+(const BigInteger & T) const //两个大数之间的相加运算 125 { 126 BigInteger t(*this); 127 int i, big; //位数 128 big = T.len > len ? T.len : len; 129 for (i = 0; i < big; i++) 130 { 131 t.a[i] += T.a[i]; 132 if (t.a[i] > MAXN) 133 { 134 t.a[i + 1]++; 135 t.a[i] -= MAXN + 1; 136 } 137 } 138 if (t.a[big] != 0) 139 t.len = big + 1; 140 else 141 t.len = big; 142 return t; 143 } 144 BigInteger BigInteger::operator-(const BigInteger & T) const //两个大数之间的相减运算 145 { 146 int i, j, big; 147 bool flag; 148 BigInteger t1, t2; 149 if (*this>T) 150 { 151 t1 = *this; 152 t2 = T; 153 flag = 0; 154 } 155 else 156 { 157 t1 = T; 158 t2 = *this; 159 flag = 1; 160 } 161 big = t1.len; 162 for (i = 0; i < big; i++) 163 { 164 if (t1.a[i] < t2.a[i]) 165 { 166 j = i + 1; 167 while (t1.a[j] == 0) 168 j++; 169 t1.a[j--]--; 170 while (j > i) 171 t1.a[j--] += MAXN; 172 t1.a[i] += MAXN + 1 - t2.a[i]; 173 } 174 else 175 t1.a[i] -= t2.a[i]; 176 } 177 t1.len = big; 178 while (t1.a[t1.len - 1] == 0 && t1.len > 1) 179 { 180 t1.len--; 181 big--; 182 } 183 if (flag) 184 t1.a[big - 1] = 0 - t1.a[big - 1]; 185 return t1; 186 } 187 188 BigInteger BigInteger::operator*(const BigInteger & T) const //两个大数之间的相乘运算 189 { 190 BigInteger ret; 191 int i, j, up; 192 int temp, temp1; 193 for (i = 0; i < len; i++) 194 { 195 up = 0; 196 for (j = 0; j < T.len; j++) 197 { 198 temp = a[i] * T.a[j] + ret.a[i + j] + up; 199 if (temp > MAXN) 200 { 201 temp1 = temp - temp / (MAXN + 1) * (MAXN + 1); 202 up = temp / (MAXN + 1); 203 ret.a[i + j] = temp1; 204 } 205 else 206 { 207 up = 0; 208 ret.a[i + j] = temp; 209 } 210 } 211 if (up != 0) 212 ret.a[i + j] = up; 213 } 214 ret.len = i + j; 215 while (ret.a[ret.len - 1] == 0 && ret.len > 1) 216 ret.len--; 217 return ret; 218 } 219 BigInteger BigInteger::operator/(const int & b) const //大数对一个整数进行相除运算 220 { 221 BigInteger ret; 222 int i, down = 0; 223 for (i = len - 1; i >= 0; i--) 224 { 225 ret.a[i] = (a[i] + down * (MAXN + 1)) / b; 226 down = a[i] + down * (MAXN + 1) - ret.a[i] * b; 227 } 228 ret.len = len; 229 while (ret.a[ret.len - 1] == 0 && ret.len > 1) 230 ret.len--; 231 return ret; 232 } 233 long long BigInteger::operator %(const long long & b) const //大数对一个int类型的变量进行取模运算 234 { 235 int i; 236 long long d = 0; 237 for (i = len - 1; i >= 0; i--) 238 { 239 d = ((d * (MAXN + 1)) % b + (long long)(a[i])) % b; 240 } 241 return d; 242 } 243 BigInteger BigInteger::operator^(const int & n) const //大数的n次方运算 244 { 245 BigInteger t, ret(1); 246 int i; 247 if (n<0) 248 exit(-1); 249 if (n == 0) 250 return 1; 251 if (n == 1) 252 return *this; 253 int m = n; 254 while (m>1) 255 { 256 t = *this; 257 for (i = 1; i << 1 <= m; i <<= 1) 258 { 259 t = t*t; 260 } 261 m -= i; 262 ret = ret*t; 263 if (m == 1) 264 ret = ret*(*this); 265 } 266 return ret; 267 } 268 bool BigInteger::operator>(const BigInteger & T) const //大数和另一个大数的大小比较 269 { 270 int ln; 271 if (len > T.len) 272 return true; 273 else if (len == T.len) 274 { 275 ln = len - 1; 276 while (a[ln] == T.a[ln] && ln >= 0) 277 ln--; 278 if (ln >= 0 && a[ln] > T.a[ln]) 279 return true; 280 else 281 return false; 282 } 283 else 284 return false; 285 } 286 bool BigInteger::operator >(const int & t) const //大数和一个int类型的变量的大小比较 287 { 288 BigInteger b(t); 289 return *this>b; 290 } 291 292 void BigInteger::print() //输出大数 293 { 294 int i; 295 cout << a[len - 1]; 296 for (i = len - 2; i >= 0; i--) 297 { 298 cout.width(DLEN); 299 cout.fill('0'); 300 cout << a[i]; 301 } 302 cout << endl; 303 }
其实这个也没多大用，大数肯定直接用Java了
