Why does this map crash VS?

[Sporech]

Hi!
I'm experimenting with C++ in visual studio and am writing a message encrypter/decrypter

I'm using a map and an array to translate the numerical values of each letter, but using a map crashes the debugger.

I call Setup() when the code starts

 void Setup()
{
	chartoint->insert(std::make_pair('a', 1));
	chartoint->insert(std::make_pair('b', 2));
	chartoint->insert(std::make_pair('c', 3));
	chartoint->insert(std::make_pair('d', 4));
	chartoint->insert(std::make_pair('e', 5));
	chartoint->insert(std::make_pair('f', 6));
	chartoint->insert(std::make_pair('g', 7));
	chartoint->insert(std::make_pair('h', 8));
	chartoint->insert(std::make_pair('i', 9));
	chartoint->insert(std::make_pair('j', 10));
	chartoint->insert(std::make_pair('k', 11));
	chartoint->insert(std::make_pair('l', 12));
	chartoint->insert(std::make_pair('m', 13));
	chartoint->insert(std::make_pair('n', 14));
	chartoint->insert(std::make_pair('o', 15));
	chartoint->insert(std::make_pair('p', 16));
	chartoint->insert(std::make_pair('q', 17));
	chartoint->insert(std::make_pair('r', 18));
	chartoint->insert(std::make_pair('s', 19));
	chartoint->insert(std::make_pair('t', 20));
	chartoint->insert(std::make_pair('u', 21));
	chartoint->insert(std::make_pair('v', 22));
	chartoint->insert(std::make_pair('w', 23));
	chartoint->insert(std::make_pair('x', 24));
	chartoint->insert(std::make_pair('y', 25));
	chartoint->insert(std::make_pair('z', 26));
}

and here's the definition

std::map<char, int>* chartoint;

Why does this happen?

[cire]

chartoint is an uninitialized pointer that points to some random place in memory. You're treating that random place in memory as if it is an object of type std::map<char, int> when it is not.

[Sporech]

How would I fix this then?
I'm relatively new to C++ and come from a Java background, sorry for the noobiness

[cire]

Don't use a pointer unless the semantics of your program require it.

#include <map>

std::map<char, int> chartoint = {
    {'a', 1},
    {'b', 2},
    {'c', 3},
    // ...
}; 

or, if you prefer the Setup route:

std::map<char, int> chartoint;

void Setup(std::map<char,int>& m)
{
    for (int i = 0; i < 26; ++i)
        m['a' + i] = i + 1;
}

int main()
{
    Setup(chartoint);
    // do stuff
}

[Sporech]

Ah!
That first solution is just what I was after (I hate doing setup functions)

Thank You!

[Thomas1965]

There is no need for a pointer. Just use a normal map.
std::map<char, int>chartoint;

There is also a much easier way to initialize your map.

#include <iostream>
#include <string>
#include <cstdlib>
#include <map>

using namespace std;

int main(void)
{
  std::map<char, int>chartoint;

  for (char ch = 'a', i = 1; i <= 26; i++, ch++)
  {
    chartoint[ch] = i;
  }
   
  for (auto it = chartoint.begin(); it != chartoint.end(); ++it)
  {
    std::cout << it->first << " = " << it->second << "\n";
  }
  system("pause");
  return EXIT_SUCCESS;
}

[Sporech]

I've now got code similar to the code that cire provided, but I get this problem:

'initializing': cannot convert from 'initializer list' to 'std::map<char,int,std::less<_Kty>,std::allocator<std::pair<const _Kty,_Ty>>> *'

and

The initializer contains too many elements

What's the problem now? it should work

[Thomas1965]

I guess you use an older version of Visual Studio. These initializer lists are available since 2012(?) 2013.

[Sporech]

I downloaded VS on my new PC about 2 weeks ago, so I presume its the 2016 version.

Here's the whole segment of code if this helps:

std::map<char, int>* chartoint = {
	{'a',1 },
	{'b',2 },
	{'c',3 },
	{'d',4 },
	{'e',5 },
	{'f',6 },
	{'g',7 },
	{'h',8 },
	{'i',9 },
	{'j',10 },
	{'k',11 },
	{'l',12 },
	{'m',13 },
	{'n',14 },
	{'o',15 },
	{'p',16 },
	{'q',17 },
	{'r',18 },
	{'s',19 },
	{'t',20 },
	{'u',21 },
	{'v',22 },
	{'w',23 },
	{'x',24 },
	{'y',25 },
	{'z',26 }
};

[Thomas1965]

This should work - without the asterik.

std::map<char, int> chartoint = 
{
	{'a',1 },
	{'b',2 },
	{'c',3 },
	{'d',4 },
	{'e',5 },
	{'f',6 },
	{'g',7 },
	{'h',8 },
	{'i',9 },
	{'j',10 },
	{'k',11 },
	{'l',12 },
	{'m',13 },
	{'n',14 },
	{'o',15 },
	{'p',16 },
	{'q',17 },
	{'r',18 },
	{'s',19 },
	{'t',20 },
	{'u',21 },
	{'v',22 },
	{'w',23 },
	{'x',24 },
	{'y',25 },
	{'z',26 }
};

[Sporech]

Aww, forgot I had the asterisk there, thanks!