2021.5.13课堂测试

（一）在utils.h和utils.c中完成16进制字符'0'-'9','A'-'F','a'-'f'与十六进制数据0-15的转换功能

utils.h

#ifndef _UTIL_H_
#define _UTIL_H_

//char Hex2Char(int i);
//int Char2Hex(char c);

int Hex2Char(int fromi,char * toc);
int Char2Hex(char fromc,int * toi);

int Bitstr2ByteArr(char * bs,char * ba);
int ByteArr2Bitstr(char * ba,char * bs);

int Int2ByteArr(int i,char * ba);
int ByteArr2Int(char * ba,int * i);

#endif

utils.c

#include<stdio.h>
#include"util.h"
char Hstr = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
char Hex2Char(int i){
if(i >= 0 && i <= 9){
return i + 0x30;
// return i + '0'
}
if(i >= 10 && i <= 15){
return i + 0x37;
// return i + 'A' - 10
}
return 0;
}

/*
int Hex2Char(int fromi,char *toc)
{
    if(fromi>=0&&fromi<=9)
    {
            *toc= fromi+'0';
    }
    else if(fromi>=10&&fromi<=15)
    {
            *toc = fromi+'A'-10;
    }
    else
    {
        printf("error");
     }
    return 0;
}
int Char2Hex(char fromc,int *toi)
{
        if(fromc>='0'&& fromc<='9')
        {
             *toi= fromc-'0';
        }
        else if(fromc>='A'&& fromc<='F')
        {
             *toi= fromc-'A'+10;

        }
        else
        {
            printf("error");
        }
        return 0;
}

*/ 

main.c

#include<stdio.h>
#include"utils.h"
int main(){
  int n1,n2;
  char c1,c2;
  printf("请输入一个0~15的数：");
  scanf("%d",&n1);
  Hex2Char(n1,&c1);
  printf("对应的16进制字符是%c\n",c1);
  printf("请输入一个16进制字符：");
  scanf("%c",&c2);
  Char2Hex(c2,&n2);
  printf("%c对应的数是%d\n",c2,n2);
}

（二）在utils.h和utils.c中完成位串与８位字节串的转换功能

main.c

#include<stdio.h>
#include"utils.h"
int main(){
  char ba[100];
  char bs[100];
  printf("input ByteArr:\n");
  scanf("%s",ba);
  ByteArr2BitStr(ba,bs);
  printf("bitstr:\n");
  printf("%s\n",bs);

  char baa[100];
  char bss[100];
  printf("input bitstr:\n");
  scanf("%s",bss);
  BitStr2ByteArr(bss,baa);
  printf("ByteArr:\n");
  printf("%s\n",baa);
  return 0;
}

utils1.c

#include<stdio.h>
#include<string.h>
#include"utils.h"

int Hex2Char(int fromi,char *toc)
{
    if(fromi>=0&&fromi<=9)
    {
            *toc= fromi+'0';
    }
    else if(fromi>=10&&fromi<=15)
    {
            *toc = fromi+'A'-10;
    }
    else
    {
        printf("error");
     }
    return 0;
}
int Char2Hex(char fromc,int *toi)
{
        if(fromc>='0'&& fromc<='9')
        {
             *toi= fromc-'0';
        }
        else if(fromc>='A'&& fromc<='F')
        {
             *toi= fromc-'A'+10;

        }
        else
        {
            printf("error");
        }
        return 0;
}
int ByteArr2BitStr(char *ba,char *bs)
{
    int i,j,L,k,a;
    L = strlen(ba);
    for(j=0;j<L;j++)
    {
        Char2Hex(ba[j],&a);
        for(i=0;i<4;i++)
        {
            bs[3*(j+1)-i+j] = a%2+'0';
            a=a/2;
        }
    }
    bs[4*L]='\0';
}
int BitStr2ByteArr(char *bs,char *ba){
   int i,k,j,L;
   L = strlen(bs);
   char string[100];int sum=0;
   if(L%4==1)
   {
     strcpy(string,"000");
     strcat(string,bs);
     k=L/4+1;
   }
   else if(L%4==2)
   {
     strcpy(string,"00");
     strcat(string,bs);
     k=L/4+1;
   }
    else if(L%4==3)
   {
      strcpy(string,"0");;
      strcat(string,bs);
      k=L/4+1;
   }
   else
   {
       k=L/4;
       strcpy(string,bs);
   }
   for(i=0;i<k;i++)
   {
       for(j=0;j<4;j++)
       {
           sum=sum*2;
           sum=sum+(string[4*i+j]-'0');
       }
       Hex2Char(sum,&ba[i]);
       sum=0;
   }
   ba[i]='\0';
}