PracticeDev/study_clang/BitArithmetic/main.cpp

/*************************************************************************
	> File Name: main.c
	> Author: TL Song
	> Mail: songtianlun@frytea.com
	> Created Time: Thu 27 Aug 2020 12:08:59 PM UTC
 ************************************************************************/

#include<stdio.h>
#include<time.h>
#include<map>
#include<iostream>

using namespace std;

int bitAdd(int num1, int num2)
{
	int exclusive_val = num1;  //异或值
	int carry_val = num2;      //进位值

	exclusive_val = num1 ^ num2;           //取第一次异或值(没有进位的异或就是相加)
	carry_val = (num1 & num2) << 1;        //取第一次进位值

	//进位值为0是循环终止条件
	while (carry_val)
	{
		int temp = exclusive_val;
		exclusive_val = exclusive_val ^ carry_val;  //异或值与进位值进行异或
		carry_val = (temp & carry_val) << 1;

	}
	return exclusive_val;

}

int add(int a, int b)
{
	return a+b;
}

int bitSubtraction(int num1, int num2)
{
	int temp = bitAdd(~num2, 1); //取反与求补差1
	return bitAdd(num1, temp);
}

int subtraction(int a, int b)
{
	return a - b;
}

int bitDivide(int x, int y) {
	int ans=0;
    for(int i=31;i>=0;i--)
    {
        // //比较x是否大于y的(1<<i)次方，避免将x与(y<<i)比较，因为不确定y的(1<<i)次方是否溢出  
        if( (x>>i) >=y )
        {
            ans+=(1<<i);
            x-= (y<<i);
        }
    }
    return ans;	
}

int divide(int a, int b)
{
	return a/b;
}

int multiply(int a, int b)
{
	return a * b;
}

int bitMultiply(int a, int b) 
{
	int ans = 0;  
    while(b)  
    {  
        if(b&1)  //b最后一位是否为1
            ans = bitAdd(ans, a);  
        a = (a<<1);  
        b = (b>>1);  
    }  
    return ans;	
}

int mulTwo(int n)
{
	return n << 1;
}

int divTwo(int n)
{
	return n >> 1;
}

int getAverage(int x, int y)
{
	return ( x + y ) >> 1;
}

int main()
{
	int i;
	int a,b;
	int result;
	int num = 10000000;
	clock_t start, finish;
	double duration;

	//printf("Test Add:\n");
	printf("Please Enter the num1: ");
	scanf("%d",&a);
	printf("Please Enter the num2: ");
	scanf("%d",&b);
	
	printf("---------------------------------------------------------------------------------------------\n");
	start = clock();
	for(i=0;i<num;i++)
		result = bitAdd(a,b);
		//	printf("Bit    add calculation result: %d, ", bitAdd(a,b));
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    add        calculation %d times total time: %f, Last result: %d\n", num,duration,result);

	start = clock();
	for(i=0;i<num;i++)
		result = add(a,b);
	//	printf("Direct add calculation result: %d, ", (a+b));
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct add        calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	printf("---------------------------------------------------------------------------------------------\n");
	start = clock();
	for(i=0;i<num;i++)
		result =bitMultiply(a,b);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    multiply   calculation %d times total time: %f, Last result: %d\n", num,duration,result);

	start = clock();
	for(i=0;i<num;i++)
		result = multiply(a,b);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct multiply   calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	printf("---------------------------------------------------------------------------------------------\n");
	start = clock();
	for(i=0;i<num;i++)
		result =bitDivide(a,b);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    divide     calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	start = clock();
	for(i=0;i<num;i++)
		result = divide(a,b);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct divide     calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	printf("---------------------------------------------------------------------------------------------\n");
	start = clock();
	for(i=0;i<num;i++)
		result = mulTwo(a);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    multiply 2 calculation %d times total time: %f, Last result: %d\n", num,duration,result);

	start = clock();
	for(i=0;i<num;i++)
		result = multiply(a,2);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct multiply 2 calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	printf("---------------------------------------------------------------------------------------------\n");
	
	start = clock();
	for(i=0;i<num;i++)
		result = divTwo(a);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    divide 2   calculation %d times total time: %f, Last result: %d\n", num,duration,result);

	start = clock();
	for(i=0;i<num;i++)
		result = divide(a,2);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct divide 2   calculation %d times total time: %f, Last result: %d\n", num,duration,result);


	printf("---------------------------------------------------------------------------------------------\n");
	start = clock();
	for(i=0;i<num;i++)
		result = getAverage(a,b);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Bit    average    calculation %d times total time: %f, Last result: %d\n", num,duration,result);

	start = clock();
	for(i=0;i<num;i++)
		result = divide(a+b,2);
	finish = clock();
	duration = (double)(finish - start) / CLOCKS_PER_SEC;
	printf("> Direct average    calculation %d times total time: %f, Last result: %d\n", num,duration,result);
	printf("---------------------------------------------------------------------------------------------\n");
}