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int
func(unsigned
int
i)
{
unsigned
int
temp = i;
temp = (temp & 0x55555555) + ((temp & 0xaaaaaaaa)>>1);
temp = (temp & 0x33333333) + ((temp & 0xcccccccc)>>2);
temp = (temp & 0x0f0f0f0f) + ((temp & 0xf0f0f0f0)>>4);
temp = (temp & 0xff00ff) + ((temp & 0xff00ff00)>>8);
temp = (temp & 0xffff) + ((temp & 0xffff0000)>>16);
return
temp;
}
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FileWriter out = ......;
Connection connection = ......;
PreparedStatement statement = ......;
try
{
ResultSet resultSet = statement.executeQuery(
"select name from users"
);
while
(resultSet.next()) {
out.write(resultSet.getString(
"name"
));
}
connection.close();
out.close();
}
catch
(Exception e) {
e.printStackTrace();
}
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#define mul(a) (a)*(a)
int main( void) { int a = 5, b, c; b = mul(a++); c = mul(++a); if(!a && c++) b++; else c++; printf( "%d %d", b, c); } |
struct data
{ int a; unsigned short b; }; int main( void) { data mData; mData.b = 0x0102; char *p = ( char *)&mData; printf( "%d %d", sizeof(mData), ( int) (*(p + 4))); } |
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#include <iostream>
using namespace std; class Base { public: ~Base() { cout << "~Base" << endl; } }; class Dri: public Base { public: ~Dri() { cout << "~Dri" << endl; } }; int main() { Base *b = new Dri(); delete b; return 0; } |
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#include <stdio.h>
#include <unistd.h> int main() { int i; for(i = 0; i < 2; ++i) { fork(); printf( "-"); fflush(stdout); } return 0; } |
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class obj { public: obj() { m = 0; data = new int[ 100]; } obj( const &t) { m = t.m; data = new int[ 100]; memcpy(( char *)data, ( char *)t.data, sizeof( int) * 100); } int squ( volatile int *p) //表示对*p的赋值,将全部保留不做优化,volatile摆放的位置不同导致的不同含义与const类似 { int tmp = *p; return tmp * tmp; } ~obj() { if(data) delete[] data; } void add() { m++; } private: int m; int *data; }; int main() { obj o1; obj o2 = o1; return 0; } |
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