counting letter grades from a file

[elduro86]

hi for my assignment i have to make a program that will read grades from a file called grade.txt and counts the number of each letter grade. I did my code and it compiles without no error but when I prompt the use for the file name, the dos window closes.can someone please help me here is my code.



#include<iostream>
#include<fstream>
using namespace std;
#include<cmath>
#include<string>




int main(void)
{
char grade;
int aCount=0,bCount=0,cCount=0,dCount=0,fCount = 0;

string filename; //declare variable filename to be a string(string is a char array)
cout<<"please enter file name to read from--->";
cin>>filename;//read file name into variable
ifstream infile; //set up pointer variable called infile
infile.open(filename.c_str()); //use function c_str() to convert value of variable filename so that .open
ofstream outfile;
outfile.open("output.txt");







while(infile>>grade){

switch(grade)
{

case 'A': case 'a': ++aCount;
break;
cout<<"the total for letter a is"<<aCount<<endl;
case 'B': case 'b': ++bCount;
break;
cout<<"the total for letter b is"<<bCount<<endl;
case 'C': case 'c': ++cCount;
break;
cout<<"the total for letter c is"<<cCount<<endl;
case 'D': case 'd': ++dCount;
break;
cout<<"the total for letter d is"<<dCount<<endl;


case 'F': case 'f': ++fCount;
break;
cout<<"the total for letter f is"<<fCount<<endl;

case '\n': case ' ': break;

default:

break;
}
}
system("pause");
return(0);
}

[matsom]

but when I prompt the use for the file name, the dos window closes.

You need to do some error checking, i.e what if the file is not found? or the user entered a wrong filename?

#include<iostream>
#include<fstream>
using namespace std;
#include<cmath>
#include<string> 

no, don't do this...