Why does it give a "multiple test case" error? - c++

Question

I've written the code for eliminating the largest 2 elements of an array, but this code gives junk value for testcase > 1. Why?
Input:
no of TestCase
size of array
elements of array
Sorting function:
int sort_asc(int arr[], int n)
{
for(int i=0;i<n;i++)
{
for(int j=i+1;j<n;j++)
{
if(arr[j]<arr[i])
{
int temp;
temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
}
}
}
int main() {
//code
int test;
cin>>test;
while(test--){
//taking size and array as inputs
int size;
cin>>size;
int a[size];
cin>>a[size];
for(int i=0;i<size;i++){
cin>>a[i];
}
//sorting the array
sort_asc(a,size);
//printing the output discarding last 2 elements of the array
for(int i=0;i<size-2;i++){
cout<<a[i]<<" ";
}
cout<<"\n";
}
return 0;
}
Expected:
12 23 28 43 44 59 60 68 70 85 88 92 124 125 136 168 171 173 179 199 212
230 277 282 306 314 316 325 328 336 337 363 365 368 369 371 374 387 394 414
422 427 430 435 457 493 506 527 531 538 541 546 568 583 650 691 730 737 751
764 778 783 785 789 794 803 809 815 847 858 863 874 887 896 916 920 926 927 930 957
My output:
12 23 28 43 44 59 60 68 70 81 85 88 92 124 125 136 168 171 173 179 199 212 230 277 282 306 314 316 325 328 336 337 363 365 368 369 371 374 387 394 414 422 427 430 435 457 493 506 527 531 538 541 546 568 583 650 691 730 737 751 764 778 783 785 789 794 803 809 815 847 858 863 874 887 896 916 920 926 930 957

Answer 1

A VLA (variable length array) is invalid C++ code. It is tolerated by some compilers, but it is still invalid.
But that is not your main problem. You produced an out of bound error. An array index starts with 0. The last element is at position size-1. So your statement
cin>>a[size];
will write past the end of your array. Producing undefined behavior.
I am not sure, why you put the statement at all, but after that, anything undefined can and most probably will happen.