Thread: ASCII values help

  1. #1
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    Oct 2010
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    ASCII values help

    Hi, i am currently trying to write a program that can read 4 input characters (ie what a user selects) and then convert the character into its ASCII decimal number. I then need the sum of these characters eg if AAAA was inputted (65+65+65+65) then the output should show 260.

    Atm the this is what i have:
    Code:
    #include <stdio.h>
    int main( void )
    {
    	     
    char input_letter;				
    				              
    input_letter = getchar(); 			
    	  
    printf("%d", input_letter ) ;
    }
    i know i'll probably need some kind of array to indetify the other 3 characters, but where im new to the language, i was wondering if anyone knows some solutions

    Grant Searle.

  2. #2
    Registered User claudiu's Avatar
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    You don't need an array per say. You can just loop around what you are doing now and add a variable to sum the values up. Are you familiar with loops? If not, I suggest checking the FAQ of this site.
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

  3. #3
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    Code:
    #include <stdio.h>
    
    int main( void )
    {
    #define LETTERNUM 4	     
      char input_letter[LETTERNUM+1];
      int i, sum = 0;
      
      fgets( input_letter, sizeof input_letter, stdin );
      if( strchr( input_letter, '\n' ) ) *strchr( input_letter, '\n' ) = 0;
      if( strlen(input_letter) != LETTERNUM )
      {
        puts("wrong letter num");
        return 1;
      }
    
      for( i=0; i<LETTERNUM; ++i )
        sum += (unsigned char) input_letter[i];
    
      printf("\nsum = %d", sum );
    
      return 0;
    }

  4. #4
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    Great idea's, but it could be done very simply:

    Code:
    #include <stdio.h>
    int main( void )
    {
      char input_letter;				
      int sum = 0;
    				              
      input_letter = getchar(); 			
      sum += input_letter;    //+= is the shorthand for sum = sum+ input_letter
    
      input_letter = getchar();             
      sum += input_letter;
      	  
      input_letter = getchar(); 			
      sum += input_letter;
    
      input_letter = getchar(); 			
      sum += input_letter;
    
      printf("%d", sum ) ;
      return 0;
    }
    That's as simple as it gets, I think. Boring, also!

    Great having you in the forum though, Grant_Searle!

    Now, what about putting the above, into a for loop:
    Code:
    int i;
    
    for(i=0;i<4;i++)  {
      input_letter=getchar();
      sum += input_letter;
    }
    
    //Now what should we do?? :p

  5. #5
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    You must input 4 times a Enter, sum is wrong for extended ASCII values.

  6. #6
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    hey guys,
    firstly thanks for all your feedback, after some reading of the FAQ's, suggestions from Adak and a bit of common sense i have written working code.
    Yes, it is boring haha but im sure i can elaborate once i understand the language a bit better.
    I will look more into loops and arrays for future programs

    Once again, thankyou.

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