两道模板题，同样与多维数组有关，需要自己实现中括号。以及各种赋值操作。
实现一个三维数组模版CArray3D，可以用来生成元素为任意类型变量的三维数组，输出指定结果
#include <iostream> #include <iomanip> #include <cstring> using namespace std; template <class T> class CArray3D { // 在此处补充你的代码 }; CArray3D<int> a(3,4,5); CArray3D<double> b(3,2,2); void PrintA() { for(int i = 0;i < 3; ++i) { cout << "layer " << i << ":" << endl; for(int j = 0; j < 4; ++j) { for(int k = 0; k < 5; ++k) cout << a[i][j][k] << "," ; cout << endl; } } } void PrintB() { for(int i = 0;i < 3; ++i) { cout << "layer " << i << ":" << endl; for(int j = 0; j < 2; ++j) { for(int k = 0; k < 2; ++k) cout << b[i][j][k] << "," ; cout << endl; } } } int main() { int No = 0; for( int i = 0; i < 3; ++ i ) { a[i]; for( int j = 0; j < 4; ++j ) { a[j][i]; for( int k = 0; k < 5; ++k ) a[i][j][k] = No ++; a[j][i][i]; } } PrintA(); memset(a[1],-1 ,20*sizeof(int)); memset(a[1],-1 ,20*sizeof(int)); PrintA(); memset(a[1][1],0 ,5*sizeof(int)); PrintA(); for( int i = 0; i < 3; ++ i ) for( int j = 0; j < 2; ++j ) for( int k = 0; k < 2; ++k ) b[i][j][k] = 10.0/(i+j+k+1); PrintB(); int n = a[0][1][2]; double f = b[0][1][1]; cout << "****" << endl; cout << n << "," << f << endl; return 0; }
无
layer 0: 0,1,2,3,4, 5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19, layer 1: 20,21,22,23,24, 25,26,27,28,29, 30,31,32,33,34, 35,36,37,38,39, layer 2: 40,41,42,43,44, 45,46,47,48,49, 50,51,52,53,54, 55,56,57,58,59, layer 0: 0,1,2,3,4, 5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19, layer 1: -1,-1,-1,-1,-1, -1,-1,-1,-1,-1, -1,-1,-1,-1,-1, -1,-1,-1,-1,-1, layer 2: 40,41,42,43,44, 45,46,47,48,49, 50,51,52,53,54, 55,56,57,58,59, layer 0: 0,1,2,3,4, 5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19, layer 1: -1,-1,-1,-1,-1, 0,0,0,0,0, -1,-1,-1,-1,-1, -1,-1,-1,-1,-1, layer 2: 40,41,42,43,44, 45,46,47,48,49, 50,51,52,53,54, 55,56,57,58,59, layer 0: 10,5, 5,3.33333, layer 1: 5,3.33333, 3.33333,2.5, layer 2: 3.33333,2.5, 2.5,2, **** 7,3.33333
内部类，多个中括号返回的类型不同。需要重载对象到指针的强制类型转换。
1 template <class T> 2 class CArray3D 3 { 4 public: 5 int layer1, layer2, layer3; 6 class CArray2D { 7 public: 8 int layer1, layer2; 9 T* inner; 10 CArray2D():layer1(1),layer2(1){ 11 inner = new T[1]; 12 } 13 void settings(int a, int b) { 14 layer1 = a; 15 layer2 = b; 16 delete[]inner; 17 inner = new T[a*b + 1]; 18 } 19 T* operator[](int b) { 20 return inner +layer2 * b; 21 } 22 operator T*() { 23 return inner; 24 } 25 }; 26 CArray2D*p; 27 CArray3D(int a,int b,int c):layer1(a),layer2(b),layer3(c){ 28 p = new CArray2D[a + 1]; 29 for (int j = 0; j < a; ++j) 30 p[j].settings(b, c); 31 } 32 CArray2D& operator[](int a) { 33 return p[a]; 34 } 35 36 };
对于一幅灰度的图像，积分图中的任意一点(x,y)的值是指从图像的左上角到这个点的所构成的矩形区域内所有的点的灰度值之和。
#include <iostream> #include <algorithm> #include <vector> using namespace std; class IntegralImage{ // 在此处补充你的代码 }; int main(){ int H, W; cin >> H >> W; int ** image = new int*[H]; for(int i=0;i<H;++i){ image[i]=new int[W]; } for(int i=0;i<H;++i) for(int j=0;j<W;++j) cin >> image[i][j]; IntegralImage it(H,W); for_each(image, image+H, it); for(int i=0;i<H;++i){ for(int j=0;j<W;++j) cout<<it[i][j]<<" "; cout<<endl; } }
第一行两个整数，分别是图像的宽、高H, W
接下来H*W的矩阵，分别代表图像的每个像素值
积分图中每个点的值, H*W的矩阵，每个像素之间用空格分开
2 3 1 2 3 1 0 0
1 3 6 2 4 7
这个题的关键在于赋值操作，是用for each，参数类型为一维的指针。中括号只有两层，所以不用像上一题一样写内部类。
1 class IntegralImage{ 2 public: 3 int H, W; 4 int **p; 5 int counts = 0; 6 IntegralImage(int a, int b) :H(a), W(b) { 7 p = new int*[H]; 8 for (int i = 0; i < H; i++) 9 p[i] = new int[W]; 10 } 11 int* operator[](int k) { 12 return p[k]; 13 } 14 void operator()(int *image) { 15 for (int j = 0; j < W; j++) { 16 if (counts == 0) { 17 if (j == 0) 18 p[counts][j] = image[j]; 19 else 20 p[counts][j] = p[counts][j - 1] + image[j]; 21 } 22 else { 23 if (j == 0) 24 p[counts][j] = p[counts - 1][j] + image[j]; 25 else { 26 p[counts][j] = p[counts][j - 1] + p[counts - 1][j] - p[counts - 1][j - 1] + image[j]; 27 } 28 } 29 } 30 counts++; 31 } 32 };
原文：https://www.cnblogs.com/erable/p/15023411.html