Trouble reading string text into an array and counting letters - arrays

Question

I am tasked to write a letter histogram which should be able to read any text and count the letters and output them in a neat way.
My question for this code so far is how to read the text into an array, I am stuck. I use two functions for this, one to read the text string into an array, and another function to output the array in this manner:
A: x
B: x
C: x
n: x
#include <iostream>
#include <string>
#include <cctype>
#include <cmath>
using namespace std;
const int ANTAL_BOKSTAVER = 26;
void berakna_histogram_abs ();
void skriv_histogram_abs (int bokstav, int antal);
int main()
{
int i;
char alfabet;
string text;
cout << "Skriv in texten: ";
getline (cin, text);
void berakna_histogram_abs();
void skriv_histogram_abs();
return 0;
}
void berakna_histogram_abs ()
{
string text;
char str[100]= {getline};
int i= 0, alfabet[26]={0}, j;
while (str[i]!='\0')
{
if (str[i] >= 'a' && str[i]<='z')
{
j = str[i] - 'a';
++alfabet[j];
}
i++;
}
}
void skriv_histogram_abs()
{
int alfabet[26]={0};
int i;
cout << "Frekvensen av alla bokstäver är: " <<endl;
for (i=0; i < 26; i++)
cout << char(i + 'a')<<" : " << alfabet[i] << endl;
}

Answer 1

One can create and pass an array as below.
Create the array once.
Pass it as parameter. The variable and parameter names may differ.
So I renamed the text variable as demonstration.
For a histogram one needs to scale the length.
int main()
{
int i;
string in_text;
cout << "Skriv in texten: ";
getline (cin, in_text);
int alfabet[26] = {0};
berakna_histogram_abs(in_text, alfabet);
skriv_histogram_abs(alfabet);
return 0;
}
void berakna_histogram_abs (string text, int* alfabet)
{
}
void skriv_histogram_abs(int* alfabet)
{
int maxfreq = 0;
int i;
for (i=0; i < 26; i++)
if (alfabet[i] > maxfreq)
maxfreq = alfabet[i];
double ratio = 60.0 / (maxfreq == 0 ? 1 : maxfreq);
cout << "Frekvensen av alla bokstäver är: " <<endl;
for (i=0; i < 26; i++)
{
cout << char(i + 'a')<<" : ";
int laengd = (int)(alfabet[i] * ratio);
for (int j = 0; j < laengd; ++j)
cout << '■';
cout << " " << alfabet[i] << endl;
}
}
Arrays are generally passed as pointers.
I scaled the bar to some 60 characters, so the line length is kept below 80.