CODEWITHSUNDEEP
c++if-statement
TheEnthusiast
TheEnthusiast

Reputation: 77

Easier way to write this if function c++

is there an easier way to write this if statement?

int main ()
{
  char k[100];
  int i=0;
  ifstream fd ("info.txt");
  while (!in.eof())
  {
    fd >> k[i]
    if (int(k[i]) != 96 || int(k[i]) != 97 || 
        int(k[i]) != 98 || int(k[i]) != 99)
            i++;
  } 
}

and so on till 122. Basically all I want to do is check if the symbol in the .txt file matches all the alphabet letters, @ sign and a " . " (period)

Is there an easier way to do all of this? Any help is much appreciated !

Upvotes: 1

Views: 111

Answers (3)

Thomas Matthews
Thomas Matthews

Reputation: 57678

Try this: 

char c;
while (fd >> c)
{
  if ((c < '`') || (c > 'c'))
  {
    k[i] = c;
    ++i;
  }
}

Usually, using character constants is more readable than their ASCII decimal equivalents.

Also, using eof in a loop is considered wrong, so place the input operation in the while expression.

Since your values are contiguous, you can use the < and > operators to reduce the number of comparisons.

Edit 1:
Another alternative is to place the valid letters into a string and search the string.

const std::string invalid_letters = "@.abcdefghijklmnopqrstuvwxyz";
while (fd >> c)
{
  if (invalid_letters.find(c) == std::string::npos)
  {
    k[i] = c;
    ++i;
  }
}

You can also use islower to detect lowercase letters.

Upvotes: 4

Malcolm McLean
Malcolm McLean

Reputation: 6406

int countemailchars(istream & is)
{
   char ch;
   int answer = 0;
   while(is.get(&ch))
   {
      if(strchr("abcdefghijklmnopqrstuvwxyz.@", tolower(ch)))
         answer++;
   }

   return answer;
}

ifstream fd ("info.txt");
int N = countemailchars(fd);

Upvotes: 0

SpiralDev
SpiralDev

Reputation: 7321

You can write your if statement like this:

    if (int(k[i]) < 96 || int(k[i]) > 122){
        i++;
    }

Upvotes: 0

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