C++函数HEX转换成ASCII码，跪求帮忙！
本帖最后由 b104748590 于 2013-01-06 00:03:50 编辑 下面是我弄的函数，HEX转ASC的，但是我怎么弄都不对。

我是想实现这样的：假如现在有16进制的 20 20 20 33 35 30 2e 30 20 20 20 我想不处理20把中间5个16进制转换成ASCII码的话就应该等于350.0
20在ASCII里面应该是（space），每次读到20都有可能报错，郁闷死了！
float Rule::HexToAsc(unsigned char *Data)
{
long val=0;

val=Data[0] - 0x30;
val=Data[1] - 0x30;
val=Data[2] - 0x30;
val=Data[3] - 0x30;
val=Data[4] - 0x30;

return (float)val;
}

本人编程新手请大家帮帮忙。
c++ hex float 编程
[解决办法]
用这个，前面忘了释放内存了：

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

float hex2asc(unsigned char* datas, int n)
{
float val;
char* str = (char*)malloc((n + 1) * sizeof(char));

memcpy(str, datas, n);
str[n] = '\0';
val = (float)atof(str);
free(str);

return val;
}

int main(int argc, char* argv[])
{
unsigned char datas[] = {0x20, 0x20, 0x20, 0x33, 0x35, 0x30, 0x2e, 0x30, 0x20, 0x20, 0x20};
printf("%f\n", hex2asc(datas, 11));

return 0;
}

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static unsigned char asc2hex[] = {
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
     0, 10, 11, 12, 13, 14, 15,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0, 10, 11, 12, 13, 14, 15,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  
 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0
};

char * strpack(const char *src, size_t len, char *dst)
{
    unsigned char *from, *to, *end;

    from = (unsigned char *)src;
    to = (unsigned char *)dst;

    for (end = to + len / 2; to < end; from += 2, to++)
        *to  = (asc2hex[*from] << 4) 
[解决办法]
 asc2hex[*(from + 1)];

    return dst;
}

int main(int argc, char *argv[])
{
    char src[] = "2020203335302e30202020";
    char *dst;
    int len;
    double d;

    len = strlen(src);
    dst = malloc(len / 2 + 1);
    dst[len / 2] = '\0';
    strpack(src, len, dst);
    d = atof(dst);

    printf("[%s]\n", dst);
    printf("[%f]\n", d);

    return 0;
}