Help! I get an 'Invalid null pointer' error

[Bianelis Liriano]

I've been trying to figure out what the invalid null pointer may be but I don't see to figure it out. Can someone help me out, maybe you can catch it?


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

struct BookInfo
{
string book_tittle;
double price;
};

struct Author
{
string author_name;
BookInfo book_author[3];
};

//function prototype
void showInfo(Author a[], int size);
void getInfo(Author a[], int size);



int main()
{

int index =3;

Author Books[3] = { {"NONE", 0}, {"NONE", 0}, {"NONE", 0}};

showInfo(Books, index);

getInfo(Books, index);

showInfo(Books, index);

system("pause");
return 0;
}

void showInfo(Author a[], int size)
{

for(int x = 0; x < size; x++)
{
cout << "The author: " << a[x].author_name << endl;

for (int y = 0; y < size; y++)
{
cout << "\tThe title: " << a[x].book_author[y].book_tittle << ", the price: $" << a[x].book_author[y].price << endl;
}
}
}


void getInfo(Author a[], int size)
{
int x, y;

cout << "\nEnter the author's name: ";
cin >> a[x].author_name;
do
{
if (a[x].author_name == "NONE")
break;
else
for(int x =0; x < size; x++)
{
for (y=0; y < size; y++)
{
cout << "Enter tittle " << (y+1) << ": ";
cin >> a[x].book_author[y].book_tittle;
if (a[x].book_author[y].book_tittle == "NONE")
break;
else
cout << "Enter prince " << (y+1) << ": ";
cin >> a[x].book_author[y].price;
}
}
} while (a[x].book_author[y].book_tittle == "NONE");
}

[Disch]

If you're running this from the debugger, when you try to access a null pointer, the program will crash and the debugger will snap on the exact line of code that is causing the problem.

Are you using a debugger? If so, can you try this and tell us what line the crash is occurring on?

[ne555]

http://www.cplusplus.com/forum/general/112111/

[Bianelis Liriano]

I am using a debugger and it says line 929.

[Disch]

Are you sure? It doesn't look like your program is 929 lines long. Was it saying line 929 in some other file?

[Bianelis Liriano]

The problem was in line 29, where I was initializing the struct array. It should of been:
{{"NONE", "NONE", 0, "NONE", 0, "NONE", 0},
{"NONE", "NONE", 0, "NONE", 0, "NONE", 0},
{"NONE", "NONE", 0, "NONE", 0, "NONE", 0}};

since it should of been initialized 7 times per element.


Thank you for your help, when you mention the line, it helped me figure out what the problem was.