Why do you not declare several variables of the same type on the same line?

Question

Why is it bad practice to declare variables on one line?

e.g.

private String var1, var2, var3

instead of:

private          


        

Answer 1

while attempting this question https://www.interviewbit.com/problems/remove-element-from-array/

Method 1 gives Memory Limit exceeded for this code:

Type 1:

int i,j;

Type 2:

int i;
int j;

type 1: Gives Memory Limit Exceeded

int removeElement  (int* A, int n1, int B) 
{
    int k=0, i;
    for(i=0;i

Whereas type 2 works perfectly fine

int removeElement  (int* A, int n1, int B) 
{
    int k=0;
    int i;
    for(i=0;i