Language: C++

#include<iostream>
using namespace std;

int main(void){
	int n = 0;
	int m = 0;
	int work = 0;
	cin >> n >> m;
	int [n][m] vector_a;
	int [m] vector_b;
	int [m] vector_ans;
	for(int i = 0; i < n; i++){		//initialize
		vector_b[m] = 0;
		vector_ans[m] = 0;
		for(int j = 0; j < m; j++){
			vector_a[n][m] = 0;
		}
	}

	for(int i = 0; i < n; i++){		//input vector_a
		for(int j = 0; j < m; j++){
			cin >> vector_a[n][m];
		}
	}
	for(int i = 0; i < m; i++){		//input vector_b
		cin >> vector_b[n];
	}
	for(int i = 0; i < n; i++){
		work = 0;
		for(int j = 0; j < m; j++){
			work += vector_a[n][m] * vector_b[m];
		}
		vector_ans[n] = work;
	}
	for(int i = 0; i < n; i++){
		cout << vector_ans[n] << endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:13: error: structured binding declaration cannot have type 'int'
    9 |         int [n][m] vector_a;
      |             ^~~
a.cc:9:13: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:9:14: error: conflicting declaration 'auto n'
    9 |         int [n][m] vector_a;
      |              ^
a.cc:5:13: note: previous declaration as 'int n'
    5 |         int n = 0;
      |             ^
a.cc:9:16: error: expected initializer before '[' token
    9 |         int [n][m] vector_a;
      |                ^
a.cc:10:13: error: structured binding declaration cannot have type 'int'
   10 |         int [m] vector_b;
      |             ^~~
a.cc:10:13: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:10:14: error: conflicting declaration 'auto m'
   10 |         int [m] vector_b;
      |              ^
a.cc:6:13: note: previous declaration as 'int m'
    6 |         int m = 0;
      |             ^
a.cc:10:17: error: expected initializer before 'vector_b'
   10 |         int [m] vector_b;
      |                 ^~~~~~~~
a.cc:11:13: error: structured binding declaration cannot have type 'int'
   11 |         int [m] vector_ans;
      |             ^~~
a.cc:11:13: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:11:14: error: conflicting declaration 'auto m'
   11 |         int [m] vector_ans;
      |              ^
a.cc:6:13: note: previous declaration as 'int m'
    6 |         int m = 0;
      |             ^
a.cc:11:17: error: expected initializer before 'vector_ans'
   11 |         int [m] vector_ans;
      |                 ^~~~~~~~~~
a.cc:13:17: error: 'vector_b' was not declared in this scope
   13 |                 vector_b[m] = 0;
      |                 ^~~~~~~~
a.cc:14:17: error: 'vector_ans' was not declared in this scope; did you mean 'wctrans'?
   14 |                 vector_ans[m] = 0;
      |                 ^~~~~~~~~~
      |                 wctrans
a.cc:16:25: error: 'vector_a' was not declared in this scope
   16 |                         vector_a[n][m] = 0;
      |                         ^~~~~~~~
a.cc:22:32: error: 'vector_a' was not declared in this scope
   22 |                         cin >> vector_a[n][m];
      |                                ^~~~~~~~
a.cc:26:24: error: 'vector_b' was not declared in this scope
   26 |                 cin >> vector_b[n];
      |                        ^~~~~~~~
a.cc:31:33: error: 'vector_a' was not declared in this scope
   31 |                         work += vector_a[n][m] * vector_b[m];
      |                                 ^~~~~~~~
a.cc:31:50: error: 'vector_b' was not declared in this scope
   31 |                         work += vector_a[n][m] * vector_b[m];
      |                                                  ^~~~~~~~
a.cc:33:17: error: 'vector_ans' was not declared in this scope; did you mean 'wctrans'?
   33 |                 vector_ans[n] = work;
      |                 ^~~~~~~~~~
      |                 wctrans
a.cc:36:25: error: 'vector_ans' was not declared in this scope; did you mean 'wctrans'?
   36 |                 cout << vector_ans[n] << endl;
      |                         ^~~~~~~~~~
      |                         wctrans