GEEK学習ノート——プログラマー面接宝典ノート(一)

#include<iostream>

using namespace std;

int func(int x)
{
    int ncount = 0;
    while (x)
    {
        ncount++;
        x = x & (x - 1);
    }
    return ncount;
}

int main()
{
    cout << func(9999) << endl;
    return 0;
}

9999：10011100001111

#include<stdio.h>

main()
{
    int b = 3;
    int arr[] = {6,7,8,9,10};
    int* ptr = arr;
    *(ptr++) += 123;
    printf("%d,%d
", *ptr, *(++ptr));
}

#include <iostream>

using namespace std;

int main()
{
    float a = 1.0f;
    cout << (int)a << endl;
    cout << &a << endl;
    cout << (int&)a << endl;
    cout << ((int)a == (int&)a) << endl;//    

    float b = 0.0f;
    cout << (int)b << endl;
    cout << &b << endl;
    cout << (int&)b << endl;
    cout << ((int)b == (int&)b) << endl;//    
}

#include <iostream>

using namespace std;

int main()
{
    unsigned char a = 0xA5;
    unsigned char b = ~a >> 4 + 1;
    cout << (int)b << endl;
    return 0;
}

#include <iostream>

using namespace std;

int func(int x, int y)
{
    return(x&y) + ((x^y) >> 1);
}
int main()
{
    cout << func(729, 271) << endl;
    return 0;
}