CODEWITHSUNDEEP
cinputcharinfinite-loop
pingu19
pingu19

Reputation: 13

How to read character until a char character?

I'm trying to do a loop that read from a file a single character until it finds '\n' or '*'.

This is the loop that I wrote:

i=0;
do { 
      fscanf(fin,"%c",&word[i]);
      i++;
    } while(word[i]!='*'&&word[i]!='\n');

Now I tried to see why it doesn't work with a debugger. When I print word[i] immediately after the fscanf it shows me the correct character but then, if I try to print word[i] while it's doing the comparison with '*' or '\n' it shows me that word[i] is '\000' and the loop never ends.

I also tried with fgetc but I have the same error.

Upvotes: 1

Views: 107

Answers (3)

FredK
FredK

Reputation: 4084

Another way:

for(;;) {
   int c = fgetc(fin);
   if ( c == EOF ) {
      break;
   word[i] = c;
   if( c == '*' || c == '\n' ) {
      break;
   }
}

Upvotes: 1

Roberto Caboni
Roberto Caboni

Reputation: 7490

You have to make sure that the character you are processing is the same you just read.

Actually you increment counter i before testing word [i], that's why your check fails.

Try instead

i=0;
do { 
      fscanf(fin,"%c",&word[i]);
    }while(word[i]!='*'&&word[i++]!='\n');

I would rather move the check in the loop (break if the condition is satisfied) leaving in the while check the test on word array length.

Upvotes: 1

Barmar
Barmar

Reputation: 780984

Your while condition is not testing the same element of word that you just read, because i++ incremented the variable before the test.

Change the test to use word[i-1] instead of word[i] to adjust for this.

BTW, word[i] = fgetc(fin); is a simpler way to read one character.

Upvotes: 0

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