[C language] convert decimal numbers to binary numbers

List of articles

• Preface
• One 、 Topic explanation
• Two 、 analysis
  • 1. Code
  • 2. Key algorithms
• summary

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Preface

OK, Today, let's talk about a simple code , This code is simple for program apes , But for learning C Language is more complicated for students , Share it now , Learn with you .

One 、 Topic explanation

The title requires ：

1. Put one [0-1023] Integers in the range are converted to unsigned binary numbers
2. If it exceeds the value or the input is a non integer, it will exit normally , Otherwise, loop conversion

I will directly share the operation interface with you , Let's first look at the interface , You should know the logical relationship of the code , Or function , Then share the code ：

1： The value entered is out of range

  As shown in the figure , Input 234, Output 11101010; If we type 3333, The exit , because 3333 More than the 1023

2： The input is a letter or not a character

  such as , Input 23, Output 10111, Input 222, Output 11011110, If input dc34, The exit

Two 、 analysis

1. Code

The code is as follows （ Example ）：

Let's learn the code together ：

#include "stdio.h"
#include "stdlib.h"
#include "string.h" 
void decToBin(int n)// Enter a number 15
{
	 int result = 0;// result 
	 int k = 1;
	 int i = 0;
	 while(n)// Divide to 0 Just stop 
	 {
		i = n % 2;					// remainder i=1	//i=1		//i=1			//i=1
		result = k * i + result;	//result=1	//result=11	//result=111	//result=1111
		k = k * 10;					//k=10		//k=100		//k=1000
		n = n / 2;					//n=7		//n=3		//n=1			//n=0 sign out 
	 }
	 printf(" The binary number we get is ：%d \n",result);//1111
}

int main() {
	char s[6];
	char *p;
	do{
	printf(" Please enter a [0-1023] Range of integers ：") ;
	gets(s);
	p=s;
	int Num=1,j=0,Num_T=0,Totle=0;
	j=strlen(s);
	while(*p!='\0')   // Enter an integer number  
	{
		if(*p<'9'&&*p>'0'){
			for(int k=1;k<j;k++)
			Num=Num*10;
		//	printf("Num=%d\n",Num);
			Num_T=(*p-'0')*Num;
			//printf("%c\n",*p);
			Totle=Totle+Num_T;
		//	printf("Totle=%d\n",Totle);
			Num=1;
			j--;
			p++;
		}
		else
		exit(0);
	}
	if(Totle>=0&&Totle<1024)
	decToBin(Totle);
	else
	exit(0);
	}while(1);
	}

2. Key algorithms

1： Decimal to binary direct code ：

	 while(n)// Divide to 0 Just stop 
	 {
		i = n % 2;					// remainder i=1	//i=1		//i=1			//i=1
		result = k * i + result;	//result=1	//result=11	//result=111	//result=1111
		k = k * 10;					//k=10		//k=100		//k=1000
		n = n / 2;					//n=7		//n=3		//n=1			//n=0 sign out 
	 }

2. Convert characters to decimal numbers , If the input is not 0-9 Characters between automatically exit ：.

while(*p!='\0')   // Enter an integer number  
	{
		if(*p<'9'&&*p>'0'){
			for(int k=1;k<j;k++)
			Num=Num*10;
		//	printf("Num=%d\n",Num);
			Num_T=(*p-'0')*Num;
			//printf("%c\n",*p);
			Totle=Totle+Num_T;
		//	printf("Totle=%d\n",Totle);
			Num=1;
			j--;
			p++;
		}
		else
		exit(0);
	}

3. Judge if the value is 0-1023, Conversion , If not , What we judge here is that the value exceeds 1023, Quit

if(Totle>=0&&Totle<1024)
	decToBin(Totle);
	else
	exit(0);

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summary

Here is a summary of the article ：
That's what we're going to talk about today , This paper simply introduces the function and key algorithm of the program , I hope everyone is happy to learn .