Solving 10385 - Duathlon (Ternary search)
[andmenj-acm.git] / 11448 - Who said crisis / bigint-2007.07.07 / BigIntegerUtils.cc
blobea00ed23ba510726a781687d5e60bee35297a438
1 /*
2 * Matt McCutchen's Big Integer Library
3 */
5 #include "BigIntegerUtils.hh"
6 #include "BigUnsignedInABase.hh"
8 /*
9 * This file includes:
10 * (1) `std::string <=> BigUnsigned/BigInteger' conversion routines easier than `BigUnsignedInABase'
11 * (2) << and >> operators for BigUnsigned/BigInteger, std::istream/std::ostream
14 std::string easyBUtoString(const BigUnsigned &x) {
15 return std::string(BigUnsignedInABase(x, 10));
18 std::string easyBItoString(const BigInteger &x) {
19 return (x.getSign() == BigInteger::negative) ?
20 (std::string("-") + easyBUtoString(x)) : (easyBUtoString(x));
23 BigUnsigned easyStringToBU(const std::string &s) {
24 return BigUnsigned(BigUnsignedInABase(s, 10));
27 BigInteger easyStringToBI(const std::string &s) {
28 return (s[0] == '-') ?
29 BigInteger(easyStringToBU(s.substr(1, s.length() - 1)), BigInteger::negative) :
30 BigInteger(easyStringToBU(s));
33 // Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'.
34 std::ostream &operator <<(std::ostream &os, const BigUnsigned &x) {
35 BigUnsignedInABase::Base base;
36 long osFlags = os.flags();
37 if (osFlags & os.dec)
38 base = 10;
39 else if (osFlags & os.hex) {
40 base = 16;
41 if (osFlags & os.showbase)
42 os << "0x";
43 } else if (osFlags & os.oct) {
44 base = 8;
45 if (osFlags & os.showbase)
46 os << '0';
47 } else
48 throw "std::ostream << BigUnsigned: Could not determine the desired base from output-stream flags";
49 std::string s = std::string(BigUnsignedInABase(x, base));
50 os << s;
51 return os;
53 // Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'.
54 // My somewhat arbitrary policy: a negative sign comes before a base indicator (like -0xFF).
55 std::ostream &operator <<(std::ostream &os, const BigInteger &x) {
56 if (x.getSign() == BigInteger::negative)
57 os << '-';
58 os << (const BigUnsigned &)(x);
59 return os;