Notes on relevant knowledge points such as original code / inverse code / complement code, size end, etc

#include<stdio.h>
int main()
{
	char a = -1;//char type  8 individual bite position 
	// Original code 10000000000000001 
	// Inverse code 11111111111111110
	// Complement code 11111111111111111
	// 
	//11111111
	//111111111111111111111
	//111111111111111111110
	//100000000000000000001
	//
	signed char b = -1;
	unsigned char c = -1;
	// Original code 10000000000000001 
	// Inverse code 11111111111111110
	// Complement code 11111111111111111
	// 
	//11111111 - c
	// The high order of unsigned numbers is directly complemented 0
	//000000000000011111111
	//
	printf("%d %d %d ", a, b, c);
	// Print a Have to be reshaped and improved , Top of complement （ Sign bit ）
	// Printed is a signed number 
	return 0;
}

#include<stdio.h>
int main()
{
	int a = -129;
	unsigned int b = -129;
	printf("%d %d\n", a, b);// Force to print signed numbers 
	printf("%u %u\n", a, b);// Force to print unsigned numbers 
	return 0;
}

#include<stdio.h>

// The compiler uses arithmetic shift right   Missing the left complement sign bit from the right 
int main()
{
	int b = 5;
	// Positive integer   Three yards are the same 
	//00000000000000000000101  Original code 
	//00000000000000000000101  Inverse code 
	//00000000000000000000101  Complement code 
	b = b >> 1;
	//00000000000000000000101
	//00000000000000000000010 -> 2 = 0*2^0 + 1*2^1
	printf("%d\n", b);
	b = b << 1;
	//00000000000000000000010
	//00000000000000000000100 -> 4 = 0*2^0 + 0*2^1 + 1*2^2
	printf("%d\n", b);

	int c = -5;
	// The first number on the left determines the symbol  1 Negative  0 Being positive 
	//10000000000000000000101  Original code 
	//11111111111111111111010  Inverse code  
	//11111111111111111111011  Complement code  =  Inverse code  + 1 
	c = c >> 1;
	//11111111111111111111011  Take the complement to move 
	//11111111111111111111101  New complement 
	//11111111111111111111100  New negative code 
	//10000000000000000000011 -> -3
	printf("%d\n", c);
	c = c << 1;
	//11111111111111111111101 
	//11111111111111111111010
	//11111111111111111111001
	//10000000000000000000110
	printf("%d\n", c);

	int d = 3;
	int e = -5;
	int f = d & e;// The complement is both 1 Just take it 1, Others are 0
	//00000000000000000000000000011 3 Complement 
	//11111111111111111111111111011 -5 Complement 
	//00000000000000000000000000011 
	printf("%d\n", f);

	int g = d | e;// The complement is both 0 Just take it 0, Others are 1
	//00000000000000000000000000011 3 Complement 
	//11111111111111111111111111011 -5 Complement 
	//11111111111111111111111111011  New complement 
	//11111111111111111111111111010
	//10000000000000000000000000101 
	printf("%d\n", g);

	int h = d ^ e;// The same in the complement is 0, Dissimilarity is 1
	//00000000000000000000000000011 3 Complement 
	//11111111111111111111111111011 -5 Complement 
	//11111111111111111111111111000  New complement 
	//11111111111111111111111110111
	//10000000000000000000000001000
	printf("%d\n", h);

	//a ^ a = 0
	//0 ^ a = a
}

 

Small endian byte order ： Put the low address in the low address

Big endian byte order ： Put the high address in the low address