在C语言中如何截取字符串

/* iMode 0:ALL, 1:Left, 2:Right*/
char* Trim(char* szStr,const char ch, int iMode)
{
    if (szStr == NULL)
        return NULL;
    char szTmp[1024*10] = { 0x00 };
    strcpy(szTmp, szStr);
    int iLen = strlen(szTmp);
    char* pStart = szTmp;
    char* pEnd = szTmp+iLen;
    int i;
    for(i = 0;i < iLen;i++){
        if (szTmp[i] == ch && pStart == szTmp+i && iMode != 2)
            ++pStart;
        if (szTmp[iLen-i-1] == ch && pEnd == szTmp+iLen-i && iMode != 1)
            *(--pEnd) = '\0';
    }
    strcpy(szStr, pStart);
    return szStr;
}

char* trim(char* input) {
    char* start = input;
    while (isSpace(*start)) { //trim left
        start++;
    }

    char* ptr = start;
    char* end = start;
    while (*ptr++ != '\0') { //trim right
        if (!isSpace(*ptr)) { //only move end pointer if char isn't a space
            end = ptr;
        }
    }

    *end = '\0'; //terminate the trimmed string with a null
    return start;
}

bool isSpace(char c) {
    switch (c) {
        case ' ':
        case '\n':
        case '\t':
        case '\f':
        case '\r':
            return true;
            break;
        default:
            return false;
            break;
    }
}

虽然不是最好的方法，但它能够工作

char* Trim(char* str)
{
    int len = strlen(str);
    char* buff = new char[len];
    int i = 0;
    memset(buff,0,len*sizeof(char));
    do{
        if(isspace(*str)) continue;
        buff[i] = *str; ++i;
    } while(*(++str) != '\0');
    return buff;
}

void inPlaceStrTrim(char* str) {
    int k = 0;
    int i = 0;
    for (i=0; str[i] != '\0';) {
        if (isspace(str[i])) {
            // we have got a space...
            k = i;
            for (int j=i; j<strlen(str)-1; j++) {
                str[j] = str[j+1];
            }
            str[strlen(str)-1] = '\0';
            i = k; // start the loop again where we ended..
        } else {
            i++;
        }
    }
}

char *
strTrim(char * s){
    int ix, jx;
    int len ;
    char * buf 
    len = strlen(s);  /* possibly should use strnlen */
    buf = (char *) malloc(strlen(s)+1);

    for(ix=0, jx=0; ix < len; ix++){
       if(!isspace(s[ix]))
          buf[jx++] = s[ix];

    buf[jx] = '\0';
    strncpy(s, buf, jx);  /* always looks as far as the null, but who cares? */
    free(buf);            /* no good leak goes unpunished */
    return s;             /* modifies s in place *and* returns it for swank */
 }

如果String.Trim无法去除嵌入的空格，则需要更多的逻辑来解决这个问题。