matrix

#include<iostream>
using namespace std;
int Input(int a[][100],int b[][100])
{
    int i,j,n;
    cout<<"Please input the columnsize:"<<endl;
    cin>>n;
    cout<<"Please input the first matrix which the size is "<<n <<"* "<<n<<":"<<endl;
    for(i=0;i<n;i++)
        for(j=0;j<n;j++)
            cin>>a[i][j];
    cout<<"Please input the second matrix which the size is "<<n <<"* "<<n<<":"<<endl;
    for(i=0;i<n;i++)
        for(j=0;j<n;j++)
            cin>>b[i][j];
    return n;
}
int addMatrix(int a[][100],int b[][100],int c[][100],int n)
{
    int i,j;
    for(i=0;i<n;i++)
        for(j=0;j<n;j++)
            c[i][j]=a[i][j]+b[i][j];
        return 0;
}
int multiplyMatrix(int a[][100],int b[][100],int d[][100],int n)
{
    int i,j,k;
    for(i=0;i<n;i++)
        for(k=0;k<n;k++)
        {
            d[i][k]=0;
            for(j=0;j<n;j++)
                d[i][k]+=a[i][j]*b[j][k];
        }
            return 0;
}
int Outputa(int c[][100],int n)
{
    int i,j;
    for(i=0;i<n;i++)
    {
        for(j=0;j<n;j++)
            cout<<c[i][j]<<" ";
        cout<<endl;
    }
    return 0;
}
int Outputm(int d[][100],int n)
{
    int i,j;
    for(i=0;i<n;i++)
    {
        for(j=0;j<n;j++)
            cout<<d[i][j]<<" ";
        cout<<endl;
    }
    return 0;
}
int main()
{
    int a[100][100];
    int b[100][100];
    int c[100][100];
    int d[100][100];
    int n;
    n=Input(a,b);
    addMatrix(a,b,c,n);
    multiplyMatrix(a,b,d,n);
    Outputa(c,n);
    Outputm(d,n);
    return 0;
}