16进制与字符串相互转换（C语言）

野性酷女 2023-06-10 03:28 13阅读 0赞

编译语言： C  
编译工具链：MinGW GCC  
编译环境：eclipse

--------------------

**字符串转换成16进制函数**  
先写一个字符转大写的函数lowtocap  
（也可以直接调用C库函数toupper，需\#include <ctype.h>）

/*lowercase letters transform to capital letter*/
    char lowtocap(char c)
    {
           if((c >= 'a') && (c <= 'z'))
           {
                  c = c - 32;       // 或者c = c + ('a' - 'A');
           }
           return c;
    }
    
    /*ascii string transform to 16 jinzhi Hex*/
    void AsciiToHex(char *src, uint8_t *dest, int len)
    {
        int dh,dl;   // 16进制的高4位和低4位
        char ch,cl;  //字符串的高位和低位
        int i;
        if(src == NULL || dest == NULL)
        {
           printf("src or dest is NULL\n");
           return;
        }
        if(len < 1)
        {
           printf("length is NULL\n");
           return;
        }
        for(i = 0; i < len; i++)
        {
           ch = src[2*i];
           cl = src[2*i+1];
           dh = lowtocap(ch) - '0';
           if(dh > 9)
           {
                  dh = lowtocap(ch) - 'A' + 10;   //lowtocap可以用库函数toupper
           }
           dl = lowtocap(cl) - '0';
           if(dl > 9)
           {
                  dl = lowtocap(cl) - 'A' + 10;   //lowtocap可以用库函数toupper
           }
           dest[i] = dh * 16 + dl;
        }
        if(len%2 > 0)   //字符串个数为奇数
        {
           dest[len/2] = src[len-1] - '0';
           if(dest[len/2] > 9)
           {
                  dest[len/2] = lowtocap(src[len-1]) - 'A' + 10;
           }
        }
    }

--------------------

**16进制转换成字符串函数**

/*16 jinzhi Hex transform to ascii string*/
    void HexToAscii(uint8_t *src, char *dest, int len)
    {
           char dh,dl;  //字符串的高位和低位
           int i;
           if(src == NULL || dest == NULL)
           {
                  printf("src or dest is NULL\n");
                  return;
           }
           if(len < 1)
           {
                  printf("length is NULL\n");
                  return;
           }
           for(i = 0; i < len; i++)
           {
                  dh = '0' + src[i] / 16;
                  dl = '0' + src[i] % 16;
                  if(dh > '9')
                  {
                         dh = dh - '9' - 1 + 'A'; // 或者 dh= dh+ 7;
                  }
                  if(dl > '9')
                  {
                         dl = dl - '9' - 1 + 'A'; // 或者dl = dl + 7;
                  }
                  dest[2*i] = dh;
                  dest[2*i+1] = dl;
           }
           dest[2*i] = '\0';
    }

--------------------

**开始测试**

#include <stdio.h>
    #include <stdlib.h>
    #include <stdint.h>
    #include <string.h>
    
    char *c1 = "ABCEEF12345678900C0B";    //待测试字符串
    uint8_t s[7] = {0xAB,0xCC,100,50,10,9,8};  //待测试16进制数组
    
    int main(void) {
        int i,len;
        uint8_t temp[30] = {0};
        char temp1[50] = {0};
    
        AsciiToHex(c1,temp, strlen(c1));
        if(strlen(c1)%2 > 0)
        {
           len = strlen(c1)/2 + 1;
        }
        else
        {
           len = strlen(c1)/2;
        }
        for( i = 0; i < len; i++)
        {
           printf("int[%d] is %X,%d\n", i+1,temp[i],temp[i]);
        }
        
        HexToAscii(s,temp1,sizeof(s));
        printf("temp1 is %s", temp1);
        return EXIT_SUCCESS;
    }

**测试结果如下：**

int\[1\] is AB,171  
int\[2\] is CE,206  
int\[3\] is EF,239  
int\[4\] is 12,18  
int\[5\] is 34,52  
int\[6\] is 56,86  
int\[7\] is 78,120  
int\[8\] is 90,144  
int\[9\] is C,12  
int\[10\] is B,11  
temp1 is ABCC64320A0908