Problem with Printf and Scanf

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Problem with Printf and Scanf

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#1 by (1 votes)

0

I want to make my program ask to enter a sentence and then a letter but even though the phrase asks for it the letter does not ask for it yet IF it shows the text "Letter:" that follows that the command line of the console starts ...

The code is this:

char frase[100];
char letra;


printf("Frase: ");

scanf("%s", frase);

printf("Letra: ");

scanf("%c", &letra);

Also, I think that if my sentence contains more than one word then I do not consider it ...

thanks!

c

asked by Edu 06.03.2018 в 22:47

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1 answer

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score 1 · Accepted Answer

With

scanf("%s", frase);

In frase all the characters that are written will be stored until:

Read all the buffer
Found a line break
A blank space is found

By this last condition, '% s' is not able to read complete lines. For this purpose you have getline :

int n;
char frase[100];

getline(frase,&n,stdin);

Although you can also try to program it on your own:

char* ptr = frase;
int c;
while( (c = getchar()) != EOF )
{
  if( *ptr == '\n' )
  {
    *ptr = 'for( int i=0; i<99; i++ )
{
  int c = getchar();
  if( c == EOF || c == '\n' )
  {
    frase[i] = 'scanf("%s", frase);
';
    break;
  }
  frase[i] = (char)c;
}

frase[99] = 'int n;
char frase[100];

getline(frase,&n,stdin);
';

printf("\n%s",frase);
';
    break;
  }
  *ptr = (char)c;
  ++ptr;
}

printf("\n%s",frase);

Or, checking that you do not exceed 100 characters:

char* ptr = frase;
int c;
while( (c = getchar()) != EOF )
{
  if( *ptr == '\n' )
  {
    *ptr = 'for( int i=0; i<99; i++ )
{
  int c = getchar();
  if( c == EOF || c == '\n' )
  {
    frase[i] = '%pre%';
    break;
  }
  frase[i] = (char)c;
}

frase[99] = '%pre%';

printf("\n%s",frase);
';
    break;
  }
  *ptr = (char)c;
  ++ptr;
}

printf("\n%s",frase);