7-4 BCD decryption (10 points)

BCD A number is a two digit decimal number expressed in one byte , Every four bits represent one bit . So if a BCD The hexadecimal number is 0x12, It expresses decimal 12. But Xiao Ming didn't learn BCD, Put all the BCD Numbers are converted into decimal output as binary numbers . therefore BCD Of 0x12 It is output as decimal 18 了 ！

Now? , Your program needs to read this wrong decimal number , Then output the correct decimal number . Tips ： You can take 18 Convert back to 0x12, And then switch back to 12.

（ Make complaints about it , In fact, this topic is 10 Decimal conversion BCD Format alphabetic 16 Base number , Don't be confused by questions ）

Extended reading Decimal to hexadecimal C Language explanation _ Learning notes , For reference only -CSDN Blog _c Language decimal to hexadecimal

Here, first explain what is BCD Count ：

Decimal 15    BIN Expressed as 1111（BIN In fact, it refers to binary data , Meet 2 Just write forward 1, Change the original position to zero , The number that has been written according to this rule ）

BCD In fact, it means Write a number in groups of binary numbers , such as ：

Decimal 15    BCD Expressed as 0001 0101

Input format ：
Input gives a... In one line [0, 153] Positive integer in range , Ensure that it can be converted back to a valid BCD Count , In other words, this integer will not appear when converted to hexadecimal A-F The number of .

Output format ：
Output the corresponding decimal number .

sample input ：
18

sample output ：
12

Reference code

#include <stdio.h>

int main()
{
    int n, cnt = 0, t = 1, num = 0;
    int s[2];

    scanf("%d", &n);
    // Decimal to hexadecimal 
    while (n)
    {
        s[cnt] = n % 16;
        t *= 16;
        n /= 16;
        cnt++;
    }
    if (s[1] != 0)
        printf("%d", s[1]);
    printf("%d\n", s[0]);

    return 0;
}

Another way to do it

#include <stdio.h>
		
int main()
{
	int i,j,k;
	scanf("%d", &i);
	j = i / 16;
	k = i % 16;
	printf("%d\n", j*10+k);
			 
	return 0;
}