运行时停止工作

我为我的大学项目编写了这段代码，但当我尝试运行它时它停止工作。任何人都可以帮助我解决问题的地方吗？我想这是指针，但我不知道它错在哪里对于 t 和 z，如果您想尝试使用 20 和 5当我输入它们时，它会停止工作而不是给我输出它应该给出 2 个.txt文件，包括一些数字

#include <iostream>
#include <fstream>
using namespace std;
int main()
{
    int t;
    int z;
    double deltaz;
    double deltat;
    double beta;
    double mv=0;
    ofstream out1("Time-setllment.txt");
    ofstream out2("isochrones.txt");
    cout<<"Enter time step(>9&integer only):";
    cin>>t;
    cout<<endl<<"Enter height step(integer only):";
    cin>>z;
    cout<<endl;
    double **u = new double * [z+1];
    for (int i=0;i<z;i++)
        u[i]=new double [t+1];
    double *s = new double [t+1];
    mv = (0.00000003*365*24*3600)/(2*10);
    deltaz = 20/z;
    deltat = 50/t;
    beta = (2*deltat)/(deltaz*deltaz);
    if (beta>0.5)
        cout<<"Beta is more than 0.5 :|"<<endl;
    else
    {
    for (int i=0;i<z+1;i++)
    {
        if (i==0 || i==z)
        {
            for (int j=0;j<t+1;j++)
                u[i][j] = 0;
        }
        else
        {
            u[i][0]=70-3.5*(i*deltaz);
        }
    }
    for (int j=1;j<t;j++)
    {
        for (int i=1;i<z;i++)
        {
            u[i][j] = u[i][j-1]+beta*(u[i-1][j-1]+u[i+1][j-1]-2*u[i][j-1]);
        }
    }
    for (int j=1;j<t+1;j++)
    {
        double sigmau=0;
        for (int i=1;i<z;i++)
        {
            sigmau +=u[i][j];
        }
        s[j]=mv*(35*20-deltaz*((u[0][j]+u[z][j])/2+sigmau));
    }

    out1<<"Time t Settlment n";
    for (int j=1;j<t+1;j++)
    {
        out1<<j*deltat<<"t"<<s[j]<<"n";
    }
    out2<<"Depth t";
    for (int j=0;j<t+1;j++)
    {
        out2<<"t(year)="<<j*deltat<<"t";
    }
    out2<<"n";
    for (int i=0;i<z+1;i++)
    {
        out2<<i*deltaz<<"t";
        for (int j=0;j<t+1;j++)
        {
            out2<<u[i][j]<<"t";
        }
    }
    for (int i=0;i<z+1;i++)
        delete []u[i];
    delete []u;
    delete []s;
    }
    return 0;
}