若有int n=10,m=20,*p=&n,*q=&m,则以下赋值话句中错误的是a,p=q,b,* p=*q, p=*q
时间: 2024-03-23 12:41:40 浏览: 19
根据您提供的信息,以下赋值语句中错误的是 `p=*q`。因为 `p` 是一个指向整型变量 `n` 的指针,而 `*q` 是整型变量 `m` 的值,类型不匹配,不能将一个整型值直接赋给一个指针变量。另外,`a` 和 `b` 都是表达式,没有被完整地给出,无法判断它们是否正确。因此,正确的代码应该是:
```c++
int n = 10;
int m = 20;
int* p = &n;
int* q = &m;
*p = *q; // 将 m 的值赋给 n,即将 20 赋给变量 n
```
这样就可以将变量 `m` 的值赋给变量 `n`。
相关问题
#include <iostream> #include <cstdlib> using namespace std; int matrixChainOrder(int p[], int n, int** m, int** s) { for(int i = 1; i <= n; i++) { m[i][i] = 0; } for(int l = 2; l <= n; l++) { for(int i = 1; i <= n-l+1; i++) { int j = i+l-1; m[i][j] = INT_MAX; for(int k = i; k <= j-1; k++) { int q = m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]; if(q < m[i][j]) { m[i][j] = q; s[i][j] = k; } } } } return m[1][n]; } int main() { int n = 3; int p[] = {8, 1, 8}; int** m = new int*[n+1]; int** s = new int*[n+1]; for(int i = 1; i <= n; i++) { m[i] = new int[n+1]; s[i] = new int[n+1]; } int minMultiplications = matrixChainOrder(p, n, m, s); cout << "The minimum number of multiplications is: " << minMultiplications << endl; cout << "The solutions to the subproblems are:" << endl; for(int i = 1; i <= n; i++) { for(int j = 1; j <= n; j++) { cout << "(" << m[i][j] << ", " << s[i][j] << ") "; } cout << endl; } for(int i = 1; i <= n; i++) { delete[] m[i]; delete[] s[i]; } delete[] m; delete[] s; return 0; }请在此代码基础上稍加修改,避免输出的矩阵元素值异常大
这段代码存在一个问题,就是在未初始化数组 `m` 和 `s` 的值时,直接对其进行赋值操作,在这种情况下,它们的值是不确定的,可能会导致输出异常大的情况。因此,我们需要在对数组进行赋值操作之前,先将它们的值初始化为 0。
修改后的代码如下所示:
```cpp
#include <iostream>
#include <cstdlib>
using namespace std;
int matrixChainOrder(int p[], int n, int** m, int** s) {
// 初始化数组 m 和 s
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
m[i][j] = 0;
s[i][j] = 0;
}
}
for(int i = 1; i <= n; i++) {
m[i][i] = 0;
}
for(int l = 2; l <= n; l++) {
for(int i = 1; i <= n-l+1; i++) {
int j = i+l-1;
m[i][j] = INT_MAX;
for(int k = i; k <= j-1; k++) {
int q = m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j];
if(q < m[i][j]) {
m[i][j] = q;
s[i][j] = k;
}
}
}
}
return m[1][n];
}
int main() {
int n = 3;
int p[] = {8, 1, 8};
int** m = new int*[n+1];
int** s = new int*[n+1];
for(int i = 1; i <= n; i++) {
m[i] = new int[n+1];
s[i] = new int[n+1];
}
int minMultiplications = matrixChainOrder(p, n, m, s);
cout << "The minimum number of multiplications is: " << minMultiplications << endl;
cout << "The solutions to the subproblems are:" << endl;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
cout << "(" << m[i][j] << ", " << s[i][j] << ") ";
}
cout << endl;
}
for(int i = 1; i <= n; i++) {
delete[] m[i];
delete[] s[i];
}
delete[] m;
delete[] s;
return 0;
}
```
修改后的代码会对数组 `m` 和 `s` 进行初始化,初始化后再进行赋值操作,从而避免输出异常大的矩阵元素值。
from Crypto.Util.number import * import gmpy2 def get_params(): a,b = [getPrime(128) for _ in range(2)] a,b = [bin(i)[2:].zfill(128) for i in [a,b]] #使用bin(i)将其转换为二进制字符串,并使用[2:]来去除开头的"0b"。(bin(i)返回的字符串形式以"0b"开头,表示该字符串是二进制表示形式) p = int((a + b),2) #上一行已经改为了二进制,那么在这里拼接后改为十进制,并且这里是运算,不会改变ab的值,拼接更不会对其改变 q = int((b + a),2) a, b = int(a, 2), int(b, 2) #将二进制字符串a和b分别转换为十进制整数,并将它们分别赋值给变量a和b。 return gmpy2.next_prime(p),gmpy2.next_prime(q),a,b flag = b'flag{******}' m = bytes_to_long(flag) p,q,a,b = get_params() n = p * q stream = [getPrime(128)] for i in range(114): num = (a * stream[-1] + b) % p stream.append(num) e = gmpy2.next_prime(stream[1] * stream[14] + stream[51] * stream[4]) c = pow(m,e,n) print(f'n = {n}') print(f'c = {c}') # n = 6983103504667653623549839927036982238702989760981440695828662474048376735590137382537887815211794982723527122829225808557810219686458488017050037179654123 # c = 6796222297027759937096057530534388748539384795006307524526800462652134886498275107011127280721467103062302906430290388832305421496018525958278394725734527 请写出解密脚本
解密脚本如下:
```python
from Crypto.Util.number import long_to_bytes
import gmpy2
def get_params():
a,b = [getPrime(128) for _ in range(2)]
a,b = [bin(i)[2:].zfill(128) for i in [a,b]]
p = int((a + b),2)
q = int((b + a),2)
a, b = int(a, 2), int(b, 2)
return gmpy2.next_prime(p),gmpy2.next_prime(q),a,b
def decrypt(c, p, q, a, b):
phi_n = (p - 1) * (q - 1)
d = gmpy2.invert(e, phi_n)
m = pow(c, d, n)
return long_to_bytes(m)
n = 6983103504667653623549839927036982238702989760981440695828662474048376735590137382537887815211794982723527122829225808557810219686458488017050037179654123
c = 6796222297027759937096057530534388748539384795006307524526800462652134886498275107011127280721467103062302906430290388832305421496018525958278394725734527
e = gmpy2.next_prime(stream[1] * stream[14] + stream[51] * stream[4])
p,q,a,b = get_params()
plaintext = decrypt(c, p, q, a, b)
print(f'Plaintext: {plaintext.decode()}')
```
请注意,解密脚本中的 `stream` 数组在给定的代码中没有明确定义,因此需要根据上下文做适当的调整。此外,需要确保 `gmpy2` 库已正确安装。