find method in a stack - visual-c++

Question

I've implemented a method to find a value from a 'Stack'. I just want to know that are there any logical errors or any kind of errors in this code?
Thanks.
bool about::findData(char key)
{
if(top==-1)
cout<<"Stack is Empty"<<endl;
else
{
for(int x=0; x<maxSize-1; x++)
{
if(stackArray[x]==key)
return stackArray[x];
}
}
}

Answer 1

I don't really know what you want to do / ask. From a logical point of view this program will work.
But you got some hops and jumps in there. I will start with a working example and point out the differences.
Note that I won't address the stack logic in itself. It seems like you did start out with a stack like thing, but got driven quite away from it?
You have a (top == -1) query in there, but never ever declared top / assigned a value to it. I assumed that you meant the size of the array (not that this is probably not the best way to calculate the array size, especially as C++ has a vector container anyways).
You iterate over maxSize elements, yet didn't declare maxSize anywhere. This also assumes that your stack is of fixed size and all elements are initiated with a sane value. I am just iterating over the size of the current array right now.
You return the value return stackArray[x];, yet declared your function to have a bool return value - this does no harm in itself, but I went for returning true and false to adhere to the return value.
Try the code online.
#include <iostream>
using namespace std;
int maxSize = 10;
char stackArray[] = {'b', 'a', 'c', 'd'};
//char stackArray[] = {};
bool findData(char key)
{
int top = (sizeof(stackArray)/sizeof(*stackArray));
cout << "Size of array is: " << top << endl;
if(top <= 0)
cout<<"Stack is Empty"<<endl;
else
{
for(int x=0; x<top; x++)
{
if(stackArray[x]==key)
return true;
}
return false;
}
}
int main() {
if(findData('a')) {
cout << "We found the value!" << endl;
} else {
cout << "We didn't find the value!" << endl;
}
}
EDIT
And as I couldn't resist I jump started with an array based stack architecture from here and implemented our beloved findValue within this stack.
#include <iostream>
#include <string>
using namespace std;
class Stack {
private:
int top;
int capacity;
int *storage;
public:
Stack(int capacity) {
if (capacity <= 0)
throw string("Stack's capacity must be positive");
storage = new int[capacity];
this->capacity = capacity;
top = -1;
}
void push(int value) {
if (top == capacity)
throw string("Stack's underlying storage is overflow");
top++;
storage[top] = value;
}
int peek() {
if (top == -1)
throw string("Stack is empty");
return storage[top];
}
void pop() {
if (top == -1)
throw string("Stack is empty");
top--;
}
/* Our findValue function. */
bool findValue(int key) {
/* Now the usage of top makes perfect sense,
the counter variable always contains the amount
of stored elements. */
if (top == -1) {
throw string("Stack is empty");
}
/* We traverse all elements of our storage. */
for (int i = 0; i < top; i++) {
if(storage[i] == key) {
return true;
}
}
return false;
}
bool isEmpty() {
return (top == -1);
}
~Stack() {
delete[] storage;
}
};
int main() {
/* Init the new stack. */
Stack* stack = new Stack(10);
/* Push some elements for more fun. */
stack->push('a');
stack->push('b');
stack->push('c');
stack->push('d');
stack->push('e');
stack->push('f');
/* Show charcode of last pushed element. */
cout << stack->peek() << endl;
/* Find 'e'. */
if (stack->findValue('e')) {
cout << "We found the value" << endl;
}
/* Try and not find 'g'. */
if (!(stack->findValue('g'))) {
cout << "We didn't find the value" << endl;
}
delete stack;
return 0;
}