单词翻转

if(start==NULL || end==NULL)return;
    while(start<end){
        char temp=*start;
        *start=*end;
        *end=temp;
        start++;
        end--;
    }
}

char *reverse(char *str){
    if(str==NULL)return NULL;
    char *begin=str;
    char *last=strlen(str)-1;
    char *index=str;
    reverse(begin, last);
    while(*index!=‘\0‘){
        while(*index==‘ ‘){
            index++;
            begin++;
        }
        if(*index==‘\0‘)return str;
        while(*index!=‘ ‘ && *index!=‘\0‘){
            index++;
        }
        reverse(begin, index-1);
        begin=index;    
    }
    return str;
}