2013科大讯飞笔试

填空题 有STL库由哪部分组成，
简答题：1.冒泡排序和快速排序的优缺点
              2.进程和线程共同使用的技术（好像是这么说的）
              3.指针和引用的区别
              4.析构函数和普通成员函数的区别
编程题（c,c++,java都可以，但不能用库函数）

            1.识别一个字节中按位置1的个数，尽量用高效率的方法实现

            2.编程实现一个类中只能实例化3次

            3.实现一个字节中空格个数不能超过一个，例如a--b-c应该输出a-b-c,此处-代表空格

#include<stdio.h>

int main(int argc,char *argv[])
{
	char a = 0x1f;
	int n = 0;
	while(a)
	{
		//n += a & 0x01;
		//a >>= 1;
		a &= a-1;
		n++;
	}
	printf("%d\n",n);
	return 0;
}

#include<iostream>

class finalclass
{
public: static int count;
public:
	static finalclass *getinstance()
	{
		if(count <= 0)
			return NULL;
		count--;
		return new finalclass;
	}
	static void setcount(int n)
	{
		count = n;
	}
/*	static void deleteinstance(finalclass *pinstance)
	{
		delete pinstance;
		pinstance = 0;
	}
*/
private:
	finalclass(){}
	~finalclass(){}
};
int finalclass::count = 0;
int main()
{
	finalclass::setcount(3);
	finalclass *f1 = finalclass::getinstance();
	finalclass *f2 = finalclass::getinstance();
	finalclass *f3 = finalclass::getinstance();
	if(f3 == NULL)
		printf("f3 NULL\n");
	else
		printf("f3 NOT NULL\n");
	finalclass *f4 = finalclass::getinstance();
	if(f4 == NULL)
		printf("f4 NULL\n");
	finalclass *f5 = finalclass::getinstance();
	if(f5 == NULL)
		printf("f5 NULL\n");
}

#include<stdio.h>

int main(int argc,char *argv[])
{
	char str[128] = "a   b  c";
	int state = 0,i = 0;
	printf("%s\n",str);
	while(str[i])
	{
		if(state == 0 && str[i-1] == ' ' && str[i] == ' ')
			state = 1;
		if(state == 1 && str[i] != ' ')
			state = 0;
		if(state == 0)
			printf("%c",str[i]);
		i++;
	}
	return 0;
}

#include<stdio.h>

char str[128] = "./a.out   100   200"; 
int argc = 0,state = 0,i = 0;
char *argv[20] = {};
void parse()
{
	while(str[i])
	{
		if(state == 0 && str[i] != ' ')
		{
			state = 1;
			argv[argc++] = str + i;
		}
		if(state == 1 && str[i] ==' ')
		{
			state = 0;
			str[i] = '\0';
		}
		i++;
	}
}
int main(void)
{
	printf("%s\n",str);
	parse();
	printf("argc=%d\n",argc);
	for(i = 0;i < argc;i++)
		printf("%s\n",argv[i]);
}