Sec homework

[Superdaddyyu]

目录

1写一个模指数运算函数Mod_Exp，输入a、b和m，输出a^b mod m，即a的b次方模m。

2写一个求乘法逆元的函数Mul_Inverse，输入a和m，求a模m的乘法逆元。提示，要求只输出正整数。

3第四章习题:1、5、6、8

 

1

int Mod_Exp(int a, int b, int m)
{
	int s = a;
	for (int i = 0; i < b; i++)
	{
		s *= a;
	}
	int mod;
	mod = s % m;
	return mod;
}
int main()
{
	int a, b, m;
	cin >> a >> b >> m;
	cout << Mod_Exp(a, b, m);
	return 0;
}

2

void inverse(int a, int m) 
{
int r0 = 1, s0 = 0;
int r1 = 0, s1 = 1;
int k;
while (m != 0) 
{
	int t = a;
	k = a / m;
	a = m;
	m = t % m;
	int r = r0, s = s0;
	r0 = r1;
	s0 = s1;
	r1 = r - k * r1; 
	s1 = s - k * s1;
}

if (a != 1)
 { 
cout << "数据错误！" << endl;
 }
else 
 { 
cout << r0 << endl; 
 }
}
int main() {
	int a, m;
	cin >> a >> m;
	inverse(a, m);
	return 0;
}

3