自己写 的trim有点问题

char * trim(char *desc){ if(!desc) {  return NULL; }

 while(*desc == ' ' && *desc != '/0') {  desc ++; }

 int len = strlen(desc); if(len == 0) {  return NULL; }

 char *pCh = desc+len-1; while (*pCh == ' ') {  pCh --; } *(pCh++)='/0';

 if(strlen(desc)==0) {  return NULL; }

 return desc;}