Fledgling Xiao Li's 108th blog binary print

Introduction to binary printing

C Language has a lot of format control when formatting and printing , For example, decimal printing %d Output , Hexadecimal use %x Output , Octal uses %o Format output , But when we expect to see the binary of a data, we must use a calculator or other inconvenient tools, so we consider writing a simple binary printing function .

Principle of binary printing

The internal storage of the computer is binary, so whether it is signed or unsigned, it is binary , utilize C The bit operation of language can realize the access to each bit , Here I just want to output binary , I don't want to record this number, so what I print is 2 String composed of hexadecimal characters .

Binary print code

void printf_2(int data)
{
    
	int i = 0;
	for(i = 0;i<32;i++)
	{
    
		if(data&(0x80000000>>i)) 
		{
    
			printf("1");
		}
		else 
		{
    
			printf("0");
		}
	}
	printf("\r\n");	
} 

Test code

	printf(" test 1： The argument is a positive decimal number ： %d\r\n",2147483647); 
	printf_2(2147483647);
	printf(" test 2： The argument is a decimal negative number ： %d\r\n",-1); 
	printf_2(-1);	
	printf(" test 3： The parameter is a hexadecimal number ： 0x%X\r\n",0x80010000); 
	printf_2(0x80010000);

Running results

Explanation of results

Positive test

The highest bit of a signed number is its Sign bit So print 2147483647 The highest result is 0;

Hexadecimal number test

Negative test

Because negative numbers exist in the form of complements in computers -1 The printout is -1 Complement