第8题和13题通不过，求教。

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
int main() {
    int t;
    double p;
        p=3.141593;
    cin>>t;
    switch(t) {
        case 1:
            cout<<"I love Luogu!";break;
        case 2:
            cout<<2+4<<" "<<10-2-4<<endl;break;
        case 3:
            cout<<3<<endl<<4*3<<endl<<14-4*3<<endl;break;
        case 4:
            printf("%6.3f\n",0.1*5000/3);break;
        case 5:
            cout<<(260+220)/(12+20)<<endl;break;
        case 6:
            cout<<sqrt(6*6+9*9)<<endl;break;
        case 7:
            int n;
            n=100+10;
            printf("%d\n",n);
            n=n-20;
            printf("%d\n",n);
            n=0;
            printf("%d",n);break;
        case 8:
            cout<<2*5*p<<endl;
            cout<<p*5*5<<endl;
            cout<<4.0/3*p*5*5*5<<endl;
            break;
        case 9:
            int a;
            a=1;
            a=(a+1)*2;
            a=(a+1)*2;
            a=(a+1)*2;
            cout<<a<<endl;break;
        case 10:
            cout<<9<<endl;break;
        case 11:
            cout<<1.0*100/(8-5);break;
        case 12:
            char b;int k;
            k=1;
            b='A';
            while(b!='M') {b++;  k++;
            }
            cout<<k<<endl;
            b='A';
            for(int i=1;i<18;i++) b++;
            cout<<b;
            break;
        case 13:
            double v1;
            v1=4/3*p*(4*4*4+10*10*10);
            v1=pow(v1,1.0/3);
            cout<<(int)v1;
            break;
        case 14:
            int x;
            for(int i=1;i<=110;i++){
                x=i*(10+110-i);
                if(x==3500) {
                    cout<<i;return 0;
                }
            }
            break;
        default :
            cout<<"error";
    }
    return 0;
}