C语言将int型数据转换为十六进制的字符串

方法一：

int i =0;
char * inttohex(int aa,char *buffer)
{
    if (aa < 16)            //递归结束条件
    {
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
        buffer[i+1] = ""; //字符串结束标志
    }
    else
    {
        inttohex(aa / 16,buffer);  //递归调用
        i++;                //字符串索引+1
        aa %= 16;           //计算当前值
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
    }


    return (buffer);
}

由于使用了全局变量i来记录下标，每次在调用函数转换前都需要将将i设置成0；

方法二，使用静态变量：

char * inttohex(int aa,char *buffer)
{
    static int  i = 0;
    i = 0;
    if (aa < 16)            //递归结束条件
    {
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
        buffer[i+1] = ""; //字符串结束标志
    }
    else
    {
        inttohex(aa / 16,buffer);  //递归调用
        i++;                //字符串索引+1
        aa %= 16;           //计算当前值
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
    }


    return (buffer);
}

测试代码如下：

char * inttohex(int aa,char *buffer)
{
    static int  i = 0;
    i = 0;
    if (aa < 16)            //递归结束条件
    {
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
        buffer[i+1] = ""; //字符串结束标志
    }
    else
    {
        inttohex(aa / 16,buffer);  //递归调用
        i++;                //字符串索引+1
        aa %= 16;           //计算当前值
        if (aa < 10)        //当前数转换成字符放入字符串
            buffer[i] = aa + "0";
        else
            buffer[i] = aa - 10 + "a";
    }


    return (buffer);
}



int my_strLength(char *str)
{
    int len = 0;
    while (*str != "") {
        len++;
        str++;
    }
    return len;
}


char * getCRC2(char *string,char *buffer)
{
    int len = my_strLength(string);
    int sum = 0;
    for (int i=0; i<len; i++) {
        sum += (string[i] + i%10);
    }

    int low = sum & 0xffff;//获取低16位
    return inttohex(low,buffer);
}

int main(int argc, const char * argv[]) {
    
    char buffer1[5],buffer2[5],buffer3[5];
    char *str1 = "aaaaaaafadsfasdf";
    char *rs1 = getCRC2(str1,buffer1);
    printf("rs===>:%s 
",rs1);
    
  
    char *str2="bbbfffa";
    char *rs2 = getCRC2(str2,buffer2);
    printf("rs2===>:%s 
",rs2);

    char *str3 = "cccccccaaa";
    char *rs3 = getCRC2(str3,buffer3);
    printf("rs3===>:%s 
",rs3);
    
    return 0;
}