need help.

[ttiimm13]

it compiles but when i run it i get a segmentation fault.
im using unix.

  #include <iostream>
#include <string>
using namespace std;

class bag
{

public:
bag(){n=0; array[30];}
bool add( string item);
bool remove(string item);
int getCurrentSize(){ cout<<"size of bag"<<n<<endl;}
bool isEmpty(){if(n != 0) return false; else return true;}
void clear(){ n=0;}
int getFrequencyOf(string item);
bool contains (string item);
void display();


private:
int n;
string array[];
};

bool bag::add(string item)
{
int m=n;
while(n>=0)
{array[n]=item;
n++;
}
if(m<n)
return true;
else
return false;
}

bool bag::remove(string item)
{
int m = n;
string temp;
for (int i = 0;i<n;i++)
{
   if(item == array[i])
        { temp= array[n-1];
        array[n-1]=array[i];
        n--;
}
}
        if(m>n)
        return true;
        else
         return false;
}
int bag::getFrequencyOf(string item){
int i = 0;
int count=0;
 while ((i < n) && (item != array[i])) i++;
{       if(array[i]==item)
count++;
} return count;
}
bool bag::contains (string item){
for(int i=0;i<n;i++)
{if(item==array[i])
return true;
}}
void bag::display(){
for(int i=0; i<n; i++)
cout<<array[i]<<endl;
}



main program



#include <iostream>
#include <string>
#include "bag.h"
using namespace std;

int main() {
  // Declarations
  bag groceries;                 // default ctor
  string item;

  // test add items
  cout << "*** TEST 1 add() \n";
  groceries.add("milk");
  groceries.add("meat");
  groceries.add("carrots");
  groceries.add("fish");

  // test display()
  cout << "*** TEST 2 display()\n";
  groceries.display();

  // test remove()
  cout << "*** TEST 3 remove()\n";
  groceries.remove("carrots");

  groceries.display();

  // test clear()
  cout << "*** TEST 4 clear()\n";
  groceries.clear();

  groceries.display();

  // test isEmpty()
  cout << "*** TEST 5 isEmpty()\n";
  if (groceries.isEmpty())
    cout << "Bag is empty\n";
  else
    cout << "Bag is not empty\n";

  // TEST add() boolean return
  cout << "*** TEST 6 add() boolean return\n";
  cout << "Enter an item or 'quit': ";
  cin >> item;
  while (item != "quit") {
     if (!groceries.add(item))
        cout << "ERROR - bag is full!\n";
     cout << "Enter an item or 'quit': ";
     cin >> item;
  }

  groceries.display();

  // TEST contains()
  cout << "*** TEST 7 contains()\n";
  cout << "Enter an item to search for: ";
  cin >> item;
  if (groceries.contains(item))
    cout << item << " found\n";
  else
    cout << item << "not found\n";

  cout << "\nAdding two more of " << item << " to the list\n";
  groceries.add(item);
  groceries.add(item);

  groceries.display();

  // test of getfrequency Of()
  cout << "*** TEST 8 getFrequencyOf()\n";
  cout << item << " is in the list " << groceries.getFrequencyOf(item) << " times\n";

  cout << "\n\n****** TEST COMPLETE ******\n";

}

[Peter87]

My compiler wrote:

// Line 9
// warning: statement has no effect
array[30];

This accesses the 31th element in the array. For this to work the array needs to be at least of size 31. This statement is a bit pointless because you're not using the value for anything.

My compiler wrote:

// Line 12
// warning: no return statement in function returning non-void
int getCurrentSize(){ cout<<"size of bag"<<n<<endl;}

You probably don't want want to use cout in this function and instead use a return statement to return the size.

My compiler wrote:

// Line 22
// warning: ISO C++ forbids zero-size array ‘array’
string array[];

You need to specify the size of the array between []. If you don't want a fixed size you should consider using std::vector.

My compiler wrote:

// Line 63
// warning: control reaches end of non-void function
bool bag::contains (string item){
for(int i=0;i<n;i++)
{if(item==array[i])
return true;
}}

You need to return a value also in the case when the item is not found.