#include #include #include #include #include #include #include #include using namespace std;
// 實現兩個數的加法
// 判斷乙個字串是否為有效的數
bool isvalidnumber( const string &s )
if( 1 == len && ( '+' == s[0] || '-' == s[0] ) )
for( int i = 0; i < len; i++ )
else
} }
return ret;
}// 實現兩個正數的加法
string twopositiveplus( const string &lhs, const string &rhs )
int len1 = lhs.length();
int len2 = rhs.length();
int len = len1 > len2 ? len1 + 2 : len2 + 2;
result.resize(len);
string lhs1 = lhs;
string rhs1 = rhs;
if( '+' == lhs[0] )
if( '+' == rhs[0] )
int len11 = lhs1.length();
int len22 = rhs1.length();
int i = 0;
int j = 0;
int up = 0;
int idx = 0;
for( i = len11 - 1, j = len22 - 1; i >= 0 && j >= 0; i--, j-- )
else
} while( i >= 0 )
else
i--;
} while( j >= 0 )
else
j--;
} if( 1 == up )
result[idx] = '\0';
result.resize( idx + 1 );
for( i = 0, j = idx - 1; i < j; i++, j-- )
return result; }
// 正數加上負數
string posiveaddnegative( const string &lhs, const string &rhs )
int len1 = lhs.length();
int len2 = rhs.length();
int len = len1 > len2 ? len1 + 2 : len2 + 2;
result.resize(len);
string lhs1 = lhs;
string rhs1 = rhs;
if( '+' == lhs[0] )
if( '-' == rhs[0] )
int flag = lhs1.compare( rhs1 );
if( 0 == flag )
int isminus = 0;
int len11 = lhs1.length();
int len22 = rhs1.length();
if( ( len11 == len22 && flag < 0 ) || len11 < len22 )
int up = 0;
int idx = 0;
int i = 0;
int j = 0;
len11 = lhs1.length();
len22 = rhs1.length();
//cout << lhs1 << ' ' << rhs1 << endl;
for( i = len11 - 1, j = len22 - 1; i >= 0 && j >= 0; i--, j-- )
else
}//cout << i << ' ' << j << ' ' << result[0] << endl;
while( i >= 0 )
else
i--;
} while( j >= 0 )
else
j--;
} result[idx] = '\0';
idx + 1 );
//cout << "result=" << result << endl;
for( i = 0, j = idx - 1; i < j; i++, j-- ) //逆置一下
//cout << idx << ' ' << "result=" << result << endl; // 0001
int k = 0;
int cur = 0;
while( '0' == result[k] )
while( k <= idx )
result[cur] = '\0';
result.resize( cur + 1 ); //預留乙個字元給符號位
//cout << result << " sf" << ' ' << cur << endl;
idx = cur;
if( 1 == isminus ) //結果為負數
result[0] = '-';
result[ idx + 1 ] = '\0';
result.resize( idx + 2 );
} //cout << result << endl;
return result;
}int judgeaddtype( const string &s1, const string &s2 )
if( s1[0] != '-' && s2[0] != '-' )
else if( s1[0] != '-' && '-' == s2[0] )
else if( '-' == s1[0] && s2[0] != '-' )
else if( '-' == s1[0] && '-' == s2[0] )
return type;
}// 大數乘法
/*思想：
0 1 2 3 4
0 1 2
-----------------------
20 21 22 23 24
10 11 12 13 14
00 01 02 03 04
------------------------------------
*/string multipy( const string &s1, const string &s2 )
// 任意元素為0，乘積為0
if( ( 1 == s1.length() && '0' == s1[0] ) || ( 1 == s2.length() && '0' == s2[0] ) )
bool ispositive = true;
if( ( '-' == s1[0] && s2[0] != '-' ) || ( s1[0] != '-' && '-' == s2[0] ) )
string ss1 = s1;
string ss2 = s2;
if( !isdigit(s1[0]) )
if( !isdigit(s2[0]) )
int len1 = ss1.length();
int len2 = ss2.length();
int *presult = new int[ len1 + len2 ];
if( null == presult )
for( int i = 0; i < len1 + len2; i++ )
for( int i = len1 - 1; i >= 0; i-- ) }
for( int i = len1 + len2 - 1; i >= 1; i-- ) }
char *pch = new char[ len1 + len2 + 1 ];
if( null == pch )
int k = 0;
while( 0 == presult[k] ) // 跳過頭部0元素
int idx = 0;
if( !ispositive )
for( ; k < len1 + len2; k++ )
pch[idx] = '\0';
if( !ispositive )
string result(pch);
delete pch;
pch = null;
delete presult;
presult = null;
return result;
}int main()
else if( 0 == type ) // 正+正
else if( 1 == type ) // 正+負
else if( 2 == type ) // 負+正
else if( 3 == type ) // 負+負
}return ret;
}
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