Ví dụ mảng 2 chiều trong C/C++

/*
Vi du 1 [ mang 2 chieu ]
 - Nhap vao tu ban phim ma tran vuong chua cac so nguyen co kich thuoc n (3<=n<=8)
 - In ma tran vua nhap
 - Dem so chan trong ma tran
 - Tinh tong theo dong cua ma tran

 - Tim so lon nhat, nho nhat tron ma tran
 - In ra vi tri xuat hien cac so nguyen to trong ma tran

*/

#include<iostream>
#include<conio.h>
using namespace std;
int a[8][8],n;

void Nhap(){
do{
    cout<<"\n n= ";
    cin>>n;
    if(n<3||n>8)
    cout<<"\n Nhap lai n!";
}while(n<3||n>8);
// Nhap ma tran
cout<<"\n Nhap ma tran: ";
for(int i=0;i<n;i++)
    for(int j=0;j<n;j++) {
        cout<<"\n a["<<i<<"]["<<j<<"]= ";
        cin>>a[i][j];
    }
}
// In ma tran
void InMaTran(){
    cout<<"\n IN MA TRAN VUA NHAP: \n";
    for(int i=0;i<n;i++) {
        for(int j=0;j<n;j++)
        cout<<a[i][j]<<"\t";
        cout<<"\n";
    }
}
// Dem so phan tu chan trong ma tran
int DemSoChan(){
    int d=0;
    for(int i=0;i<n;i++)
        for(int j=0;j<n;j++)
            if(a[i][j]%2==0)
                d++;
    return d;
}
// Tinh tong dong
void TongDong(){
    cout<<"\n Tong theo dong cua ma tran: \n";
    int s;
    for(int i=0;i<n;i++){
        s=0;
        for(int j=0;j<n;j++)
            s=s+a[i][j];
            cout<<"\n Tong dong "<<i<<" : "<<s;
    }
}
// Ham kiem tra so nguyen to
int TestSoNT(int a){
    for(int i=2;i<a;i++)
        if(a%i==0)
            return 0;
    return 1;
}
// In ra vi tri so nguyen to
void ViTriSoNT(){
    cout<<"\n VI TRI CAC SO NGUYEN TO TRONG MA TRAN: \n";
    for (int i=0;i<n;i++)
        for(int j=0;j<n;j++)
            if(TestSoNT(a[i][j])==1)
                cout<<"["<<i<<"]["<<j<<"] ;";
}
// ham chinh
int main(){

    Nhap();
    InMaTran();
    cout<<"\n So so chan trong ma tran: "<<DemSoChan();
    TongDong();
    ViTriSoNT();
    return 0;
}