I've check all the data here..but i still get WA#12..

#include <iostream>
#include <cstring>
#include <string>
#define inf 214748364
using namespace std;
struct tmono
{
    int n[9000];
    int w,nega,xs;
};
char s[1000];
int xs,len,con,e;
tmono num;
string res;
inline bool isnum(char ch)
{
    return '0'<=ch&&ch<='9';
}
inline bool getnum(int st,int en,tmono &e)
{
    memset(e.n,0,sizeof(e.n));
    e.w=0;e.xs=0;e.nega=0;
    if(s[st]=='-')    e.nega=1,++st;
    else
    if(s[st]=='+')    e.nega=0,++st;
    /*
    while(s[st]=='+'||s[st]=='-')
    {
        if(s[st]=='-')
            e.nega=!e.nega;
        ++st;
    }
    */
    for(int i=en;i>=st;i--)
    if(s[i]=='.')
    {
        e.xs=en-i;
        for(int j=i;j<en;j++)
            s[j]=s[j+1];
        --en;
        break;
    }
    for(int i=st;i<=en;i++)
    if(!isnum(s[i]))
        return 0;
    e.w=0;
    for(int i=en;i>=st;i--)
        e.n[++e.w]=s[i]-'0';
    return 1;
}
inline bool work()
{
    res="";
    cin>>xs;
    int tempxs=xs;
    scanf("\n");
    if(s[0]=='.')
    {
        for(int i=len-1;i>=0;i--)
            s[i+1]=s[i];
        s[0]='0';
        len++;
    }
    if(!isnum(s[0])&&s[0]!='-'&&s[0]!='+')
        return 0;
    con=0;
    for(int i=0;i<len;i++)
    {
    if(s[i]=='e'||s[i]=='E')
    {
        if(con!=0)
            return 0;
        con=i;
    }
    if(s[i]!='e'&&s[i]!='E'&&s[i]!='-'&&s[i]!='+'
        &&s[i]!='.'&&!isnum(s[i]))
            return 0;
    if(s[i]=='.'&&!isnum(s[i+1]))
        return 0;
    }
    e=0;
    bool enega=0;
    if(con!=0)
    {
        e=-inf;
        int j=con;
        con++;
        if(s[con]=='+'||s[con]=='-')
        {
            if(s[con]=='-')    enega=!enega;
            con++;
        }
        /*
        while(s[con]=='-'||s[con]=='+')
        {
            if(s[con]=='-')    enega=!enega;
            ++con;
        }*/
        for(int i=con;i<len;i++)
        {
            if(!isnum(s[i]))
                return 0;
            if(e==-inf)
                e=0;
            e=e*10+s[i]-'0';
            if(e>500)
                break;
        }
        if(e==-inf)
            return 0;
        if(enega)
            e*=-1;
        len=j;
    }
    --len;
    if(!getnum(0,len,num))
        return 0;
    num.xs-=e;
    while(num.n[num.w]==0&&num.w>0)
        --num.w;
    bool isxs=0;
    if(num.xs<=0)
    {
        for(int i=num.w;i>=1;i--)
            res+=num.n[i]+'0';
        while(num.xs<0)
        {
            res+="0";
            num.xs++;
        }
    }else
    {
        int j=max(num.w,num.xs);
        if(num.xs>num.w)
        {
            num.w=num.xs;
            num.xs=0;
            res+="0.";
            isxs=1;
        }
        for(int i=j;i>=1;i--)
        {
            if(i==num.xs)
                isxs=1;
            if(isxs&&xs==0)
                break;
            if(i==num.xs)
                res+=".";
            if(isxs)--xs;
            res+=num.n[i]+'0';
        }
    }
    while(xs>0)
    {
        if(!isxs)
            res+=".",isxs=1;
        res+="0",--xs;
    }
    while(res[0]=='0')
        res.erase(0,1);
    if(res.length()==0)
        res.insert(0,"0");
    if(res[0]=='.')
        res.insert(0,"0");
    for(int i=0;i<res.length();i++)
    if(res[i]=='.')
        if(res.length()-i<tempxs)
        {
            tempxs-=res.length()-i;
            while(tempxs--)
                res.insert(res.length()-1,"0");
        }else
            res.erase(i+tempxs,res.length()-i-tempxs-1);
    if(res[res.length()-1]=='.')
        res.erase(res.length()-1,1);

    if(num.nega)
    for(int i=0;i<res.length();i++)
    if('1'<=res[i]&&res[i]<='9')
    {
        res.insert(0,"-");
        break;
    }
    for(int i=1;i<res.length();i++)
    if(res[i]=='.'&&!isnum(res[i-1]))
    {
        res.insert(i,"0");
        break;
    }
    if(res[res.length()-1]=='.')    res.erase(res.length()-1,1);

    res+="\n";
    return 1;
}
inline void reads()
{
        memset(s,0,sizeof(s));
        gets(s);
        len=strlen(s);
        while(len>=1&&isspace(s[len-1]))
            s[len]=0,--len;
        while(isspace(s[0]))
        {
            for(int j=0;j<len-1;j++)
                s[j]=s[j+1];
            s[len]=0;len--;
        }
}
int main()
{
    #ifndef ONLINE_JUDGE
    freopen("input.in","r",stdin);
    freopen("output.out","w",stdout);
    #endif
    reads();
    while(!(strlen(s)==1&&s[0]=='#'))
    {
        if(!work())
            printf("Not a floating point number\n");
            else
            cout<<res;
        reads();
    }
    return 0;
}

Check that:

S12.0
2
#

where S is a space (" ").
My AC program says that its not a correct number because of leading space.

"For each pair of lines your program should write to an output a message: "Not a floating point number", if the string S is not a correct <real number>..."

<real number> does not contain spaces. =)

Good luck!

Many thanks!!!really a helpful suggest!
now I got AC.
thanks again!

Edited by author 23.03.2010 05:23