String from file to ASCII

**kilastria** · 04-27-2006

Hey,
Im having trouble converting each character from a string in a file to ASCII. I tried to use inFile and put each character into a variable, then convert the variables using static_cast<int>, but I keep getting a huge number. Any pointers would be appreciated. Thanx.

**Tonto** · 04-27-2006

Code please.

**kilastria** · 04-27-2006

ok, heres the code;

Code:

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;
int main()
{
    int r1;
    char num1, num2, num3, num4, num5, num6, num7, num8, num9, num10;
    char num11, num12, num13, num14, num15, num16, num17, num18, num19, num20;
    //declare other variables here
    
    ifstream inFile; //declare the input file
    char filename[20];//filename is used to store the name of the input file
    
      cout << "Enter the name of the input file: "<<flush; //enter the name of the input file
    cin >> filename; //read the name of the input file
    inFile.open(filename); //open the input file 
    
    
    // ************************************************************ //    
    //                   Write your code here                       //
    
    inFile >>num1>>num2>>num3>>num4>>num5>>num6>>num7>>num8>>num9>>num10 
           >>num11>>num12>>num13>>num14>>num15>>num16>>num17>>num18>>num19>>num20;
    
    r1 = static_cast<int>(num1+num2+num3+num4+num5+num6+num7+num8+num9+
      num10+    num11+num12+num13+num14+num15+num16+num17+num18+num19+num20);
    
    cout<<r1<<endl;
   cout<<num1<<num2<<num3<<num4<<num5<<num6<<num7<<num8<<num9<<num10<<
   num11<<num12<<num13<<num14<<num15<<num16<<num17<<num18<<num19<<num20<<endl;

  
    
        inFile.close(); //close the input file 

    cout << endl;                                 
cout << "Press CTR-C to Leave..." << endl;    
pause();                                      
return 0;                                                                                                       
}

The files contain strings such as:

How are you?

**whiteflags** · 04-27-2006

It would be much easier just to do something like, read in the strings, shove them in a string variable. and use the copy algorithm. An easy ostream_iterator<int>(fstream, " "); can output the ASCII code to another file.

**kilastria** · 04-28-2006

I didnt really want to move the information to another file, because I need it to do more calculations. This bit is really bugging me, and its the first step in the prgram, everthing else Ive been able to do, but using numbers iv inputted.

**Bench82** · 04-28-2006

I'm not sure I follow - The file contains text/strings? or numerical data?

You can retrieve strings from a file in exactly the same way you retrieve them from the user with cin.

I recommend you get rid of <cstring> and use the C++ std::string instead from the <string> header. Then you can retrieve a line of input from your ifstream with the following:

Code:

std::ifstream ifs("test.txt");
std::string myString;
std::getline(ifs, myString);

**Bench82** · 04-28-2006

Apologies.. I see now - You're accumulating the sum of the numerical ASCII codes... maybe something like this?

Code:

std::ifstream ifs("test.txt");
int sum(0);
while(ifs)
    sum += static_cast<int>(ifs.get());

**hk_mp5kpdw** · 04-28-2006

Originally Posted by Bench82

I'm not sure I follow - The file contains text/strings? or numerical data?

You can retrieve strings from a file in exactly the same way you retrieve them from the user with cin.

I recommend you get rid of <cstring> and use the C++ std::string instead from the <string> header. Then you can retrieve a line of input from your ifstream with the following:

Code:

std::ifstream ifs("test.txt");
std::string myString;
std::getline(ifs, myString);

That plus:

Code:

#include <numeric>

...

int sum = std::accumulate( myString.begin(), myString.end(), 0 );

Is all you need to get the sum of the value of all the characters in a string.

Originally Posted by Bench82

Code:

while(ifs)
    sum += static_cast<int>(ifs.get());

That won't quite work, it runs one extra time through the loop (returning -1) because the stream doesn't get set to eof until after you read past the end of the file.

**kilastria** · 04-28-2006

hmmm..that would be all fine and dandy, except I cant change the header files. I tried to use static_cast<int> to change from char to ASCII, but the compiler complains. I think it has something to do with the char[20]. I think I have to do something with arrays, but I havent learnt them yet. I think Im about to resign to the fact that I have failed this task miserably. I know its so simple though! agh!driving me nuts!

**kilastria** · 04-28-2006

im gonna try

Code:

while(ifs != inFile.eos())
      sum+=static_cast<int>(ifs.get());

maybe that will stop it running through too many times?!

**Bench82** · 04-29-2006

Originally Posted by hk_mp5kpdw

That won't quite work, it runs one extra time through the loop (returning -1) because the stream doesn't get set to eof until after you read past the end of the file.

Good point, I didn't think about that.

Originally Posted by kilastria

maybe that will stop it running through too many times?!

Unfortunately not. The problem as hk_ pointed out, is that ifs.get() occurs after the while condition is evaluated (in both cases, the stream is in a good state until after ifs.get() is called at the point of EOF - causing -1 to be added). a better solution might be to put the ifs.get() inside the while brackets.

Code:

ifstream ifs("test.txt");
int sum(0);
char c;
while(ifs.get(c))
    sum += static_cast<int>(c);

This stops if the stream is empty, hence keeps the -1 from being added to sum

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