数据转换

在util.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

util.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

main.c

#include<stdio.h>
#include"util.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);
}

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;
}

*/

运行结果：