IC210: Pointers & Arrays II [HW]

Name: ____________________________________________________ Alpha: _____________________

Describe help received: _________________________________________________________________

(9 Pts) Suppose we want to read an array size from user, but worry about the user entering 0 or a neg. num.

int n;
cin >> n;
double *Z;
Z = new double[n];
if (n <= 0)
{
  cout << "Error!" << endl;
  Z = new double[10];
}
Z[0] = 5;
...

int n;
cin >> n;
if (n <= 0)
{
  cout << "Error!" << endl;
  double *Z = new double[10];
}
else
  double *Z = new double[n];
Z[0] = 5;
...

int n;
cin >> n;
double *Z;
if (n <= 0)
{
  cout << "Error!" << endl;
  Z = new double[10];
}
else
  Z = new double[n];
Z[0] = 5;
...

compile-time error / possible run-time error / OK
If error, why?

(9 Pts) Suppose we want to search for int x in array A of size n.

int i = 0;
while(A[i] != x && i < n)
  i++;
if (i == n)
  cout << "Not found!";
else
  cout << "Found!";
cout << endl;

int i = 0;
while(i < n && A[i] != x)
  i++;
if (i == n)
  cout << "Not found!";
else
  cout << "Found!";
cout << endl;

for(int i = 0; i < n && A[i] != x; i++)
  ;
if (i == n)
  cout << "Not found!";
else
  cout << "Found!";
cout << endl;

works / doesn't work
If doesn't work, why?

(82Pts) Write a program that will read in a file of points in a format like this:
```
N = 6
X:	1	1.5	2	3.1	6	8.3
Y:	5.5	5.2	5.1	5.2	5.7	6.6
```
and output them as ordered pairs, i.e. like this:
```
(1,5.5) (1.5,5.2) (2,5.1) (3.1,5.2) (6,5.7) (8.3,6.6)
```
Turn In a screen capture of your program running on the file Input.txt and the source code for your program. (Hint: This is most easily done with two arrays.)