#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
char *text;
bool dpp=true;
void comments();/* (* Comments *) */
void alu(); /* (1+2+3(5+6+7))  */
void mloop()
{
    while(*text&&dpp)
    {

        if(text[0]=='(')
        {
            if(text[1]=='*')
            {
                text+=2;
                comments();
                continue;
            }
            else
            {
                text+=1;
                alu();
                continue;
            }

        }
        text++;

    }
}
void alu()
{
   while(1)
   {
        if(text[0]==')')
        {
            text+=1;
            return;
        }

        else
        {
            if(text[0]=='(')
            {
                if(text[1]=='*')
                {
                    text+=2;
                    comments();
                    continue;
                }
                else
                {
                    text+=1;
                    alu();
                    continue;
                }
            }
            else
            {

                if((text[0]==' ')||(!isdigit(text[0])&&*text!='+'&&*text!='-'&&*text!='*'&&*text!='/'&&*text!='='&&*text!='\n'&&*text!='\r') )
                {

                    dpp=false;
                    return;
                }

            }
        }
        text++;

   }
}
void comments()
{
   while(*text)
   {
    if(text[0]=='*')
    {
        if(text[1]==')')
        {
            text+=2;
            break;
        }
    }
    text++;

   }
   if(!*text)dpp=false;

}
int balans()/* Test for '(' and ')' */
{
    int k=0,n=0;
    while(*text)
    {
        if(*text=='(')
        {
            text++;
            if(*text=='*')
            {
                text++;
                comments();
                if(dpp==false)return 1;
                continue;
            }
            else {k++;continue;}

        }
        else
        {
            if(*text==')')
                n++;
        }
        text++;
    }
    if (k==n) return 0;
    else return 1;
}
int main()
{
    char *txt2,*txt3;
    text=(char*)malloc(10001);
    txt3=(char*)malloc(501);
    memset(txt3,0,sizeof(txt3));
    memset(text,0,sizeof(text));
    while(!feof(stdin))
    {
        fgets(txt3,500,stdin);
        strcat(text,txt3);
        memset(txt3,0,sizeof(txt3));

    }
    txt2=text;

    if(balans()==0)
    {
        text=txt2;

        mloop();
        if(dpp) printf("YES");
        else printf("NO");
    }
    else printf("NO");



}

It's my code...
It's not clear... But it work on all test which i found on this  discuss...What can be on #8 ? +(