c/c++ 多维数组和指针
c/c++ 多维数组和指针
知识点
1，初始化多维数组，对应代码里的test1
2，遍历多维数组,除了最内层循环外，其他所有层都必须是引用类型，对应代码里的test2
3，指针和多维数组 ，对应代码里的test3
#include <iostream>
using namespace std;
int main(){
//test1 初始化多维数组
/*
int ia[3][4] = {
{0,1,2,3},
{4,5,6,7},
{8,9,10,11}
};
//ia2和ia完全相同
int ia2[3][4] = {0,1,2,3,4,5,6,7,8,9,10,11};
//只初始化每行的首元素,其他元素为默认值
int ia3[3][4] = {{1},{4},{8}};
int ia4[2][3][4] = {1};
//用ia4的首元素为ia最后一行最后一列的最后一个元素赋值
ia[2][3] = ia4[0][0][0];
//把row绑定到ia的第二行上
int (&row)[4] = ia[2];
for(auto s : row){
cout << s << ",";
}
cout << endl;
*/
//test2 遍历多维数组,除了最内层循环外，其他所有层都必须是引用类型
/*
constexpr size_t rowCnt = 3,colCnt = 4;
int ia[3][4] = {
{0,1,2,3},
{4,5,6,7},
{8,9,10,11}
};
for(size_t i = 0; i < rowCnt; ++i){
for(size_t j = 0; j < colCnt; ++j){
cout << ia[i][j] << ",";
}
cout << endl;
}
//除了最内层循环外，其他所有层都必须是引用类型
for(auto &row : ia){
for(auto &col : row){
cout << col << ",";
}
cout << endl;
}
*/
//test3 指针和多维数组
int ia[3][4] = {
{0,1,2,3},
{4,5,6,7},
{8,9,10,11}
};
//普通遍历
for(auto p = ia; p != ia + 3; ++p){
for(auto q = *p; q != *p + 4; ++q){
cout << *q << ",";
}
cout << endl;
}
//利用库函数begin和end
for(auto p = std::begin(ia); p != std::end(ia); ++p){
for(auto q = std::begin(*p); q != std::end(*p); ++q){
cout << *q << ",";
}
cout << endl;
}
//利用别名
using iar = int[4];
for(iar* p = ia; p != ia + 3; ++p){
for(int* q = *p; q != *p + 4;++q){
cout << *q << ",";
}
cout << endl;
}
}
