c++ program multiple declaraton error - syntax-error

Question

I am getting multiple declaration error in this c++ program
#include<iostream.h>
#include<conio.h>
void main ()
{ clrscr();
int a[10][10],r,q,i;
cout<<"enter how many rows and colomn you want in the matrix:";
cin>>n;
cout<<"enter the matrix \n";
for(int r=0;r<n;++r)
{
for(int q=0;q<n;++q)
{
cin>>a[r][q];
}
}
for(int i=0;i<n;i++)
{ cout<<"\n the diagnol elements are:";
cout<<a[n-i-1][i];
}
getch();
}
it is a program for finding diagnol elements in a matrix

Answer 1

That's because you have already declared the r, q, i as int at line 5 as below:
int a[10][10],r,q,i;
^^^^^
While your three for loops, again re-declares for e.g. like this:
for(int r=0;r<n;++r)
^^^
So it re-declares the same variable in above case it's r, while the other for loop q and i which is not allowed.
Two ways to solve the problem:
a. Either you remove int from your for loop.
b. Either you remove declaration of variables used in for loop from line 5.

Answer 2

The only issue i am seeing is, you are not declaring the variable "n" . Other than that, everything seems to be fine.