C++ | 数组逆序 | 问题总结

1. 源代码

   #include
   #include
   using namespace std;
   typedef int ElemType;
   const int n = 10;
   
   void MyExchange(ElemType *a, ElemType *b){
   	ElemType temp;
   	temp = *a;  
   	*a = *b;
   	*b = temp;
   }
   
   void InverseArry(ElemType  arry[n], int  n){
   	ElemType *p = & arry[0];
   	ElemType *q = & arry[ n - 1];
   	while (p < q)//指针不相遇
   
   	{
   		MyExchange(p, q);
   		p++;
   		q--;
   	}
   
   }
   
   void PrintArrya(ElemType  arry[n], int  n) {
   	fstream f1;
   	f1.open("t1.txt", ios::in | ios::app);
   	cout << "逆序操作前:" << endl;
   	for (int i = 0; i < n; i++) {
   		f1 >> arry[i];
   		cout << arry[i] << endl;
   	}
   }
   void PrintArryb(ElemType  arry[n], int  n){
   	cout << "逆序操作后:" << endl;
   	for (int i = 0; i <  n; ++i) {
   		cout <<  arry[i] << endl;
   	}
   	cout << endl;
   
   }
   
   int main()
   {
   	ElemType arry[n] ;
   	PrintArrya(arry, n);
   	InverseArry(arry, n);
   	PrintArryb(arry, n);
   	system("pause");
   	return 0;
   
   }

    

2. typedef

用途:为数据类型名 取个别名.这样就能批量声明变量

用法:

typedef char* PCHAR;

PCHAR pa, pb;  

为什么要用 typedef 关键字:

在上图中,char*类型名只声明了pa,未声明pb,pb指向字符型变量b时失败;

像这样重复定义又太繁琐.

使用typedef后:

这是目前用得到的,还有其他用途,详见此处:http://www.cnblogs.com/csyisong/archive/2009/01/09/1372363.html