input to Multidimensional array help :s

[finny798]

let's say i create a 2D array

float num[3][3];

and i ask the user to input two numbers (the row and then the collum)

cout << "Please enter the row to enter a number to" << endl;
cin >> row;
cout << "Please enter the collum to enter a number to" << endl;
cin >> collum;

the user could then enter (E.G. 2 & 3) so row = 2 and collum = 3
how would i take these numbers and make it so that in the selected cell of the array the it automatically enters a "X"? with the 2 & 3 the number would be at the bottom of teh center collum.

[Darkmaster]

if you want to enter "X" you can't use a float array.
just use std::string

the element is used like this
num[row][column];

keep in mind: a 3x3 array goes from [0][0] to [2][2]

[goth]

Arrays are numbered from 0 to n-1, in your case 3 would be out of bounds. But let's say the user has entered row=1 and column=2 (which would translate to row 2, column 3).

To insert data there you use the [] operator as such: num[row][column] = //...user data;

[Darkmaster]

@GothicFighter: There is not really a out of bounds with arrays. for example:

int main()
{
	int A[1];

	A[0] = 0;
	A[1] = 1;
	A[2] = 2;
	A[3] = 3;

	int a = A[3];
	int b = A[2];
	int c = A[1];
}

a=3
b=2
c=1

This works fine, you can try it ;)

[finny798]

ok thanks for your help :D

[PalashBansal96]

@Darkmaster
the code works fine but it saves the values to the locations just after A and overrides whatever is in there and is of course not safe, it can delete important values from the memory.

[PalashBansal96]

You can just do like this

float num[3][3];
int row , collum;  // Spelling of column is incorrect 
cout << "Please enter the row to enter a number to" << endl;
cin >> row;
cout << "Please enter the collum to enter a number to" << endl;
cin >> collum;
cout<<"Now enter the number you want to put in the cell"<<endl;
cin >> num[row-1][collum-1];

[cire]

Darkmaster wrote:

This works fine, you can try it ;)

int main()
{
	int A[1];

	A[0] = 0;
	A[1] = 1;
	A[2] = 2;
	A[3] = 3;

	int a = A[3];
	int b = A[2];
	int c = A[1];
}

On compilation:

warning C4789: buffer 'A' of size 4 bytes will be overrun; 4 bytes will be written starting at offset 12 

On running:

Run-Time Check Failure #2 - Stack around the variable 'A' was corrupted.

If by "works fine" you mean "evokes undefined behavior and may cause a segmentation fault," then we're in agreement.