C++ Question?

I need to write a program that takes characters (only alphabetical) input from the screen (ended with a period), puts them into an array, keeps count of how many there are of each character and prints out a list of the characters and their number of occurrences, sorted by their occurrence, highest to lowest. The main thing I don't know how to do is to sort the characters based on their occurrence and also the counting itself isn't completely working. Can anyone else correct this code?





#include %26lt;iostream%26gt;


#include %26lt;fstream%26gt;





int main(void)


{


using namespace std;





char chars[]="abcdefghijklmnopqrstuvwxyz";


int i;


int count[]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0...





char inp;





cin%26gt;%26gt;inp;





while(inp !='.')


{


for(i=0;i%26lt;26;++i)


{


if(inp==chars[i])


count[i]++;


}


cin%26gt;%26gt;inp;


}





cout%26lt;%26lt;"Character Count"%26lt;%26lt;endl;





for(i=0;i%26lt;26;++i)


{


if(count[i]!=0)


{


cout%26lt;%26lt;chars[i]%26lt;%26lt;" "%26lt;%26lt;count[i]%26lt;%26lt;endl;


}


}





system("pause");





return 0;


}

C++ Question?
If you don't understand some of the concepts involved you should read up on them. Ask questions if necessary.








#include %26lt;iostream%26gt;


#include %26lt;vector%26gt;


#include %26lt;algorithm%26gt;





using namespace std;





struct elementType


{


char letter;


int count;





elementType(char l, int c) : letter(l), count(c) {};


};





bool compare(elementType a, elementType b )


{


return(a.count %26gt; b.count);


}





typedef vector%26lt;elementType%26gt; Array;








int main(void)


{


//creat vector of letter/count elements


Array array;





for (char i = 'a'; i %26lt;= 'z'; ++i)


{


elementType e(i, 0);


array.push_back(e);


}





//collect input chars


char inp;


cin %26gt;%26gt; inp;





while (inp !='.')


{


if ((isalpha(inp))


%26amp;%26amp; (islower(inp)))


array[inp - 'a'].count++;





cin %26gt;%26gt; inp;


}





//sort array


sort(array.begin(), array.end(), compare);





//spit out results





cout %26lt;%26lt; "Character Count" %26lt;%26lt; endl;





for (int i = 0; i %26lt; array.size(); ++i)


{


if (array[i].count %26gt; 0)


{


cout %26lt;%26lt; array[i].letter %26lt;%26lt; " " %26lt;%26lt; array[i].count %26lt;%26lt; endl;


}


}





system("pause");





return 0;


}
Reply:Convert the user input to an ascii value. Make a dummy array the same length as the user input array. Then all you have to do is.





for(int index=0; index%26lt;userInput.length();index++)


dummy[int(userInput[index])]++;





Print it out


for(int index=0; index%26lt;userInput.length();index++)


{


if(dummy[index]%26gt;0)


cout %26lt;%26lt; "The letter " %26lt;%26lt; char(index) %26lt;%26lt; "occured" %26lt;%26lt;dummy[index] %26lt;%26lt; " times" %26lt;%26lt; endl;


}
Reply:Seems like less work to use a map





You get the letter, increment the int.





Create some iterators and use the sort algorithm.
Reply:First, your while loop probably doesn't work because you need to get an index of inp. Something like:





int idx = 0;


while (inp[idx] != ".")


{


...


...


...


idx++;


}





Second, there are much better ways to add to the count than the following, but it should still work:





for(i=0;i%26lt;26;++i)


{


if(inp==chars[i])


count[i]++;


}





Lastly, you then need to sort. To do that, you might want to replace count with a struct that's made up of a character (the letter of the alphabet) and an integer (which is the count). Then do something simple like a bubble sort on it (you can google that).





Overall, there are better/easier ways to do this, but if you want to use your code as a starting point, then you need to look at these three areas.