普通字符串转MFC字符串函数

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

int strToHex(char *ch, char *hex);
int hexToStr(char *hex, char *ch);
int hexCharToValue(const char ch);
char valueToHexCh(const int value);
int main(int argc, char *argv[])
{
char ch[1024];
char hex[1024];
char result[1024];
char *p_ch = ch;
char *p_hex = hex;
char *p_result = result;
printf("please input the string:");
scanf("%s",p_ch);

strToHex(p_ch,p_hex);
printf("the hex is:%s\n",p_hex);
hexToStr(p_hex, p_result);
printf("the string is:%s\n", p_result);
return 0;
}

int strToHex(char *ch, char *hex)
{
int high,low;
int tmp = 0;
if(ch == NULL || hex == NULL){
return -1;
}

if(strlen(ch) == 0){
return -2;
}

while(*ch){
tmp = (int)*ch;
high = tmp >> 4;
low = tmp & 15;
*hex++ = valueToHexCh(high); //先写高字节
*hex++ = valueToHexCh(low); //其次写低字节
ch++;
}
*hex = '\0';
return 0;
}

int hexToStr(char *hex, char *ch)
{
int high,low;
int tmp = 0;
if(hex == NULL || ch == NULL){
return -1;
}

if(strlen(hex) %2 == 1){
return -2;
}

while(*hex){
high = hexCharToValue(*hex);
if(high < 0){
*ch = '\0';
return -3;
}
hex++; //指针移动到下一个字符上
low = hexCharToValue(*hex);
if(low < 0){
*ch = '\0';
return -3;
}
tmp = (high << 4) + low;
*ch++ = (char)tmp;
hex++;
}
*ch = '\0';
return 0;
}

int hexCharToValue(const char ch){
int result = 0;
//获取16进制的高字节位数据
if(ch >= '0' && ch <= '9'){
result = (int)(ch - '0');
}
else if(ch >= 'a' && ch <= 'z'){
result = (int)(ch - 'a') + 10;
}
else if(ch >= 'A' && ch <= 'Z'){
result = (int)(ch - 'A') + 10;
}
else{
result = -1;
}
return result;
}

char valueToHexCh(const int value)
{
char result = '\0';
if(value >= 0 && value <= 9){
result = (char)(value + 48); //48为ascii编码的‘0’字符编码值
}
else if(value >= 10 && value <= 15){
result = (char)(value - 10 + 65); //减去10则找出其在16进制的偏移量，65为ascii的'A'的字符编码值
}
else{
;
}

return result;
}