标签:null 建行 指针 参数 不能 使用 out i++ oid
//二位数组参数传递 //1. void display1(int arr[][4], const int rows) { for (int i = 0; i < rows; i++) { for (int j = 0; j < 4; j++) { cout << arr[i][j] << ‘ ‘; } cout << endl; } cout << endl; } //2. void display2(int(*parr)[4], const int rows) { for (int i = 0; i < rows; i++) { for (int j = 0; j < 4; j++) { cout << parr[i][j] << ‘ ‘; } cout << endl; } cout << endl; } //parr[i]等价于*(parr+i) //3. void display3(int **parr, const int rows, const int cols) { for (int i = 0; i < rows; ++i) { for (int j = 0; j < cols; ++j) { cout << *((int*)parr + i * cols + j) << " "; //注意:(parr+i*cols+j), 不是(arr+i*rows+j), 不能使用parr[i][j] } cout << endl; } cout << endl; } void display4(int **parr, const int rows, const int cols) { for (int i = 0; i < rows; ++i) { for (int j = 0; j < cols; ++j) { cout << parr[i][j] << " "; } cout << endl; } cout << endl; } int main() { int rows = 3; int cols = 4; int arr[][4] = { 0,1,2,3,4,5,6,7,8,9,10,11 }; display3((int**)arr, rows, cols); cout << "=======" << endl; //动态二位数组 int **p; p = new int*[rows];//创建行指针 for (int i = 0; i < rows; ++i) { p[i] = new int[cols]; //为每一行分配空间 } for (int i = 0; i < rows; ++i) for (int j = 0; j < cols; ++j) p[i][j] = i * cols + j; display4(p, rows, cols); //删除行数组空间 for (int i = 0; i < rows; ++i) delete[] p[i]; //删除行指针 delete[] p; p = nullptr; //一次性分配空间 int **p1; p1 = new int*[rows]; p1[0] = new int[rows*cols]; for (int i = 0; i < rows; ++i) p1[i] = p1[0] + cols*i; for (int i = 0; i < rows; ++i) for (int j = 0; j < cols; ++j) p1[i][j] = i * cols + j;// 或者 *(p1[0]+i*cols+j) = i * cols + j; display4(p1, rows, cols); display3((int**)p1[0], rows, cols); delete[] p1[0]; delete[] p1; }
标签:null 建行 指针 参数 不能 使用 out i++ oid
原文地址:https://www.cnblogs.com/xslwm/p/10349842.html