I want to delete a row from a matrix - c++

Question

I'm beginner in c++, and I want to make a program that delete a row from a matrix.. Like, If I say 3 3 2
1 2 3 it need to show 1 2 3
4 5 6 7 8 9
7 8 9
The program works like this: 3 = rows, 3 = columns, 2 = the deleted row. "3 3 2" is not a row...
I wrote this :
#include <iostream>
using namespace std;
int main() {
int N, M, v[100][100];
cin>>N>>M;
int i,j,p;
cin>>p;
for (i = 1; i <= N; ++i)
for (j = 1; j <= M; ++j)
cin>>v[i][j];
for (i = 1; i <= N; ++i) {
for (j = 1; j <= M; ++j)
cout<<v[i][j]<<" ";
cout<<"\n";
}
for (i = p; i < N; ++i)
v[i][j]=v[i+1][j];
--N;
for (i = 1; i <= N; ++i){
for (j = 1; j <= N; ++j)
cout<<v[i][j]<<' ';
cout<<"\n";
}
return 0;
}
But it doesn't work.... Can someone help me?

Answer 1

modified code (it will work fine ):
#include <iostream>
using namespace std;
int main()
{
int N, M, v[100][100];
cin>>N>>M;
int i,j,p;
cin>>p;
for (i = 1; i <= N; ++i)
for (j = 1; j <= M; ++j)
cin>>v[i][j];
for (i = 1; i <= N; ++i)
{
for (j = 1; j <= M; ++j)
cout<<v[i][j]<<" ";
cout<<"\n";
}
for (i = p; i < N; ++i)
for(j=1; j<=M; ++j)
v[i][j]=v[i+1][j];
--N;
for (i = 1; i <= N; ++i)
{
for (j = 1; j <= M; ++j)
cout<<v[i][j]<<' ';
cout<<"\n";
}
return 0;
}

Answer 2

This doesn't work, what do you think j is doing in this code?
for (i = p; i < N; ++i)
v[i][j]=v[i+1][j];
--N;
You need to loop over rows and columns. Copy each column in every row greater that the row you want to delete. In other words you need nested loops here
for (i = p; i < N; ++i)
for (j = 1; j <= M; ++j)
v[i][j] = v[i+1][j];
--N;

Answer 3

You should use vector
#include <vector>
#include <iostream>
using namespace std;
int main()
{
//matrix
vector< vector<int> > V;
//To Add
for(int i=0; i<100; i++)
{
vector<int> R;
for(int j=0; j<100; j++)
{
int x;
cin>>x;
R.push_back(x);
}
V.push_back(R);
}
//To delete a row
int row_to_delete = 2;
V.erase(V.begin() + row_to_delete);
//To access
for(int i=0; i<V.size(); i++)
{
for(int j=0; j<V[i].size(); j++)
{
cout<<V[i][j];
}
}
}
vector<T> is class that use a template to create a dynamic array.
vector<int> is a var array int. V.push_back(T) you can add a element to array with type T, and with V.erase(V.begin() + int ) you can delete a element to array in this case a row. With V.size() you can take a elements count inside the array.