C++学习 --- 函数、指针和数组
#include <iostream>
using namespace std;
int main(){
int arr[10] = {1,2,3,4,5,6,7,8,9,10};
cout << "The first element is:" << arr[0] << endl;
int *p = arr;//arr is the first address of the array
cout << "Use the pointer to access the first element:" << *p << endl;
p++;
cout << "Use the pointer to access the second element:" << *p << endl;
//Use pointers to traverse the array
int * p2 = arr;
for(int i = 0;i < 10 ;i++){
//cout << arr[i] << " ";
cout << *p2++ << " ";
//p2++;
}
cout << endl;
return 0;
}
2、函数的地址传递，指针作为函数参数
总结：如果不想修改实参，就用值传递，如果想修改实参，就用地址传递。灵活使用。
#include <iostream>
using namespace std;
//实现两个数字进行交换
//值传递
void swap01(int a,int b){
int temp = a;
a = b;
b = temp;
cout << "a = " << a << endl;
cout << "b = " << b << endl;
}
//地址传递
void swap02(int *p1,int *p2){
int temp = *p1;
*p1 = *p2;
*p2 = temp;
//cout << "*p1 = " << *p1 << endl;
//cout << "*p2 = " << *p2 << endl;
}
int main(){
int a = 10;
int b = 20;
cout << "Before the exchange" << endl;
cout << "a = " << a << endl;
cout << "b = " << b << endl;
//值传递
//swap01(a,b);
//地址传递
swap02(&a,&b);
cout << "After the exchange" << endl;
cout << "a = " << a << endl;
cout << "b = " << b << endl;
return 0;
}
3.指针数组和函数
#include <iostream>
using namespace std;
/** 实现：封装一个函数，利用冒泡排序，实现对整型数组的升序排序。
** int arr[10] = {4,3,6,9,1,2,10,8,7,5};
**/
//冒泡排序,参数1：数组的首地址 参数2：数组的长度
void bubbleSort(int * arr,int len){
for(int i = 0;i < len -1;i++){
for(int j = 0;j < len -i -1;j++){
if(arr[j] > arr[j+1]){
int temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
}
//打印数组
printArray(int * arr,int len){
for(int i = 0;i < len;i++){
cout << arr[i] << " ";
}
cout << endl;
}
int main(){
//1.先创建一个数组
int arr[10] = {4,3,6,9,1,2,10,8,7,5};
int len = sizeof(arr)/sizeof(arr[0]);
//2.创建一个函数实现冒泡排序
bubbleSort(arr,len);
//3.打印排序后的数组
printArray(arr,len);
return 0;
}
//函数传递数组长度是为了让程序更加健壮灵活
