Array Initialization Function: Passing Array as Pointer: C++

Question

I'm trying to initialize arrays by passing them to an initialization function as a pointer. My program compiles with no errors, but when I run it; it prints out Character Count and stops.

This is what I have so far:

#include<iostream>
#include<cctype>
#include<string>
#include<iomanip>
using namespace std;
void initialize(int *array, int n, int value); 
int main()
{
 char ch;
 int punctuation, whitespace, digit[10], alpha[26]; 
 punctuation = 0, whitespace = 0;
initialize(digit, sizeof(digit)/sizeof(int), 0);
initialize(alpha, sizeof(alpha)/sizeof(int), 0);
while(cin.get(ch))
{
 if(ispunct(ch))
 ++punctuation;
 else if(isspace(ch))
 ++whitespace;
 else if(isdigit(ch))
 ++digit[ch - '0'];
 else if(isalpha(ch))
 {
 ch = toupper(ch);
 ++alpha[ch - 'A'];
 }
 if(whitespace > 0)
 {
 cout << "Whitespace = " << whitespace << endl;
 }
 if(punctuation > 0)
 {
 cout << "Punctuation = " << punctuation << endl;
 }
 cout << setfill('-') << setw(17) << '-' << setfill(' ') << endl;
 cout << " Character " << " Count " << endl;
 cout << setfill('-') << setw(17) << '-' << setfill(' ') << endl;
 return 0;
 }
}
void initialize(int *array, int n, int value)
{
 int i; 
 for (i = 0; i < n; ++i)
 {
 value += array[i];
 }
}

I'm not sure that I am doing anything wrong here. Although, I am a bit confused as to how pointers work after they have been passed to another function. Can someone explain?

Thank you

• MikeC: In the initialize function, print the value of n.
• hyde: "Stops"? Hangs? Crashes? Just exits?
• Ambrus: It prints Character Count then exits

Answer 1

You probably want
a)

void initialize(int *array, int n, int value)
{
 int i; 
 for (i = 0; i < n; ++i)
 {
 // no: value += array[i]; but:
 array[i] = value;
 }
}

see also std::fill

and b) move the return 0; off the while-loop-body

 cout << " Character " << " Count " << endl;
 cout << setfill('-') << setw(17) << '-' << setfill(' ') << endl;
 }
 return 0;
}

---

edit: regarding a)
You can use

std::fill(std::begin(digit), std::end(digit), 0);
std::fill(std::begin(alpha), std::end(alpha), 0);

instead of your initialize() function or (given the context) just

int punctuation, whitespace, digit[10]={0}, alpha[26]={0}; 

• Ambrus: Oh wow, now I feel really stupid, because I didn't even notice that return 0; was inside the while loop, and the way you corrected my function is the way I had it originally. Thanks, VolkerK.

Answer 2

If you are developing in C++, why not use vectors instead? (Working with arrays* is very C style).

vector<int> array(n, value);

n = number of integers. value = value to place in each array cell.