CODEWITHSUNDEEP
cscanf
James Linden
James Linden

Reputation: 1125

Is there a way to read a c-string and then an int with a single scanf in C?

Hey, I'm trying to get this function to get the following output with the listed input, the "..." is where I'm not sure what to write:

void Question8(void)
{
  char sentence[100];    
  int grade;    
  scanf(….);    
  printf("%s %d", sentence, grade);    
}

Input:
My CS Grade is 1000

Output:
My CS Grade is 100

However, the kicker is that I need the scanf to read a c-string and then an int with a single scanf command, is this even possible?

Edit: I can only edit the code in the location with the three periods ( "..." ), I cannot use anything more. I can assume that the input listed is expected but I cannot change anything outside of the three periods. The output does not contain typos, the purpose of this assignment is to use flags and escape sequences.

Upvotes: 4

Views: 561

Answers (4)

Tony Delroy
Tony Delroy

Reputation: 106068

I'll get this over with quick:

<obligatory_rant>
    stupid question, but I guess it's homework and you're
    stuck with these absurd limitations
</obligatory_rant>

Then, if you need to read everything up to but excluding the first digit, then the number:

if (scanf("%100[^0-9] %3d", text, &number) == 2)
    ...

Notes:

  • 100 in "%100[... should be whatever your actual buffer size is to protect against buffer overrun.
  • The %3d documents that at most 3 digits should partake the the numeric value, so 1000 is correctly read as 100.
  • [^...] means the string made up of characters not ("^") in the following set, which is then specified as 0-9 - the digits.
  • if (... == 2) tests whether both positional parameters were scanned / converted successfully.

If you can't add an if and error message, then simply:

scanf("%100[^0-9] %3d", text, &number)

Upvotes: 2

CB Bailey
CB Bailey

Reputation: 791441

This is a really horrible question. A correct set of scanf parameters would be "%14c%3d", sentence, &grade

Because a space is included in the printf statement the trailing space needs to not be stored in sentence. Because the input contains other spaces there is no other solution (that I can thing of) than a fixed length. The integer parsing also requires a fixed length to truncate 1000 to 100.

I can think of no reason to ever write code anything like this. The code fits the requirements but wouldn't be useful in any other circumstances. I think that this is a very poor training exercise.

Upvotes: 0

Siddiqui
Siddiqui

Reputation: 7840

Tested in Visual Studio 2008

#include <stdio.h>

    int main()
    {
      char sentence[100];    
      int grade = 0;    
      scanf("%[^0-9] %d",sentence,&grade);
      printf("%s %d", sentence, grade);   
      return 1;
    }


Input : 
My CS Grade is 100
Output :
My CS Grade is 100

Upvotes: 1

Shamim Hafiz - MSFT
Shamim Hafiz - MSFT

Reputation: 22064

It is possible to read pre-formatted string using scanf, however the format must be strict. This version will continue to read the input until a digit is encountered and then read an integer. Here is your code again:

  char sentence[100];
  int grade;
  scanf("%[^0-9] %d",sentence,&grade);
  printf("%s %d\n", sentence, grade);

Upvotes: 2

Related Questions