411.cpp

C++实训教程

/*
	411.CPP
	演示函数调用的副作用
*/
#include <iostream.h>
float SumSquare(const float a[],int num);
float SumSquare1(float a[],int num);

main()
{
	const int SIZE = 5;
	float f[SIZE] = { 1.1, 2.2, 3.3, 4.4, 5.5};
	cout <<"Sum of Square= "  << SumSquare( f ,SIZE) <<endl;
	cout <<"Sum of Square1= "  << SumSquare1( f ,SIZE) <<endl;//调用时有了副作用
	int i;
	for (i=0; i<SIZE ; i++)
		cout << f[i]<<"  ";//改变了原来的数据
	return 0 ;
}
/* 定义函数：	 ↓用数组名作为参数，也可以这样说明参数类型float * a	*/
float SumSquare(const float a[],int num)
{
	int i;
	float sum = 0;
	for (i=0; i<num ; i++)
	{
		sum += a[i]*a[i];
	}
	return sum;
}
float SumSquare1(float a[],int num)
{
	int i;
	float sum = 0;
	for (i=0; i<num ; i++)
	{
		a[i] *= a[i];//改变了原来的数据 
		sum += a[i];
	}
	return sum;
}

/*
Sum of Square= 66.55
Sum of Square1= 66.55
1.21  4.84  10.89  19.36  30.25


*/