第8课：二维数组（统计）

a[i][j]=x;

swap(a[i][j], a[k][h]);  

int s=0;
for (int i = 1; i <= m; i++)  
{
    for (int j = 1; j <= n; j++)  
    {
        if (a[i][j]==k)  
	    {
            s++; 
        }
    }
}
cout << s;

for (int i = 0; i <= m-1; i++)  
{
    for (int j = 0; j <= n-1; j++)  
    {
        cout<<a[i][j]<<" ";
    }
    cout<<endl;   // 每行结尾都要换行
}