/*C语言去除字符串首尾空格，trim()函数实现https://blog.csdn.net/u013022032/article/details/50521465*/ #include 
    
      #include 
     
       #include 
      
        #include 
       
         //去除尾部空白字符 包括\t \n \r  /*标准的空白字符包括：' '     (0x20)    space (SPC) 空格符'\t'    (0x09)    horizontal tab (TAB) 水平制表符    '\n'    (0x0a)    newline (LF) 换行符'\v'    (0x0b)    vertical tab (VT) 垂直制表符'\f'    (0x0c)    feed (FF) 换页符'\r'    (0x0d)    carriage return (CR) 回车符//windows \r\n linux \n mac \r*/ char *rtrim(char *str) {     if (str == NULL || *str == '\0')     {         return str;     }     int len = strlen(str);     char *p = str + len - 1;     while (p >= str && isspace(*p))     {         *p = '\0'; --p;     }     return str; } //去除首部空格 char *ltrim(char *str) {     if (str == NULL || *str == '\0')     {         return str;     }     int len = 0;     char *p = str;    while (*p != '\0' && isspace(*p))     {         ++p; ++len;     }     memmove(str, p, strlen(str) - len + 1);     return str; } //去除首尾空格 char *trim(char *str) {     str = rtrim(str);     str = ltrim(str);     return str; } void demo() {     char str[] = "   ab  c \r \n \t";    printf("before trim:%s\n", str);     char *p = trim(str);     printf("after trim:%s\n", p); } int main(int argc, char **argv) {     demo();     return 0; }