StrToHex():

unsigned long nlData = 0;

char *p;

nlData = strtoul("123456",&p,16);

IntToMem():

int main(int argc, char* argv[])
{
 printf("Hello World!\n");
 char szBuf[1024] = {0};
 memcpy(szBuf,"\x70\x40",2);
 memcpy(szBuf+2,"\x60\x50",2);
 return 0;
}