printing numbers as a rectangle with nested for loops in c++ - c++

Question

I am a beginner in programming.
I am currently writing a code that takes the number 1 to 9 of rows and columns from the user. for single digits, there should be a "0"
the output should look like this:
Type a row number between 1 and 9: 3
Type a column number between 1 and 9:7
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
This is the code i currently have:
#include <iostream>
int main() {
int r,c,i,j,n,k;
cout<<"Type a row number between 1 and 9: ";
cin>>r;
while (r<1 || r>9){
cout << "Please enter a number between 1 and 9.";
cin>>r;
}
cout<< "Type a column number between 1 and 9: ";
cin>>c;
while (c<1 || c>9){
cout << "Please enter a number between 1 and 9.";
cin>>c;
}
n=r*c;
for(k=0; k<n; k++){
}
for(i=0; i<r; i++)
{
for(j=0; j<c; j++)
{
cout<<i<<" ";
}
cout << endl;
}
return 0;
}
I've added validity statements for the users.
This outputs:
Type a row number between 1 and 9: 3
Type a column number between 1 and 9:7
0 0 0 0 0 0 0
1 1 1 1 1 1 1
2 2 2 2 2 2 2
I can't figure out the 0 and how to implement the numbers into the rectangle.
Please help.

Answer 1

You're close, just change your output loop to:
int counter = 1;
for (i = 0; i < r; i++)
{
for (j = 0; j < c; j++)
{
cout << counter << " ";
++counter;
}
cout << endl;
}
If you would like to avoid the extra local variable you can also just do:
cout << (i*c + j + 1) << " ";
I would prefer the explicit version using counter as it makes it obvious what you're doing and you can easily switch the order of the loops/output if desired.