void trim(char *s, const int len)
{
    int end = len - 1;
    int start = 0;
    int i = 0;

    while ((start < len) && (s[start] <= ' '))
    {
        start++;
    }

    while ((start < end) && (s[end] <= ' '))
    {
        end--;
    }

    if (start > end)
    {
        memset(s, '\0', len);
        return;
    }

    for (i = 0; (i + start) <= end; i++)
    {
        s[i] = s[start + i];
    }
    memset((s + i), '\0', len - i);
}

http://blog.srikanths.net/2008/10/trim-for-c.html

Trim function for strings in C++

c

C++