调用函数，求a+aa+aaa+...(n个a)之和

[zj631160360]

输入两个正整数a和n，求a+aa+aaa+...aaa...aa(n个a)之和，要求并调用函数fn(a,n),它的功能是返回aa...aa(n个a).例如fn(3,2)的返回值是33

[unituniverse2]

f(a,n) = (pow(10, n) - 1) / 3, (1 <= n)
剩下的你自己推导...

[loongee]

作业帖，鉴定完毕……

[aiminxiaomao]

这个很简单吧int fn(a,n){
int temp;
while(n>=2){
temp += a*10^(n-1);
n--;}
temp += a;
return temp;
}

[unituniverse2]

不好意思刚看到你的数字去了...
f(a,n) = a * (pow(10, n) - 1) / 9, (其中1 <= n)

∑(a,n) = a * (10 * (pow(10, n) - 1) / 9 - n) / 9, (其中1 <= n)

[浪~迹天涯]

int CalcSum()
{
int a;
int n;
int rt = 0;
cin >> a >> n;
for(int i = 1;i <= n;i++)
{
rt += fn(a, i);
}
return rt;
}

[Coder_Y_Jao]

你要的fn(n个a)和求和函数sum

unsigned int fn(unsigned int a, unsigned int n)
{
	unsigned int num = 0;
	for(unsigned int i = 0; i < n; i++)
	{
		num = num * 10 + a;
	}
	return num;
}

unsigned int sum(int a, int n)
{
	unsigned int num = fn(a, n);
	if(1 == n)
	{
		return a;
	}
	else
	{
		return fn(a, n - 1) + num;
	}
}