Why I got WA?
#include<iostream>
using namespace std;
int main()
{
    int newsen=1,i,l;
    char str[99999];
    while(cin.getline(str,255))
    {
        l=strlen(str);
        for(i=0;i<l;i++)
        {
            if(str[i]<=64 || str[i]>=91)
            {
                if(str[i]!='!' && str[i]!='?' && str[i]!=':' && str[i]!=',' && str[i]!='-' && str[i]!='.' && str[i]!=' ') continue;
                cout<<str[i];
                if(str[i]=='.' || str[i]=='?' || str[i]=='!') newsen=1;
                continue;
            }
            if(newsen==1)
            {
                cout<<str[i];
                newsen=0;
            }else cout<<(char)(str[i]+32);
        }
        cout<<endl;
    }
    //system("pause");
    return 0;
}