Can someone help me with this small piece of code

This is a discussion on Can someone help me with this small piece of code within the C Programming forums, part of the General Programming Boards category; Okay, so I have this piece of code here to input a string from user and convert it to a ...

  1. #1
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    Can someone help me with this small piece of code

    Okay, so I have this piece of code here to input a string from user and convert it to a string half of the size. It works for all inputs except for ones with Zeroes in the middle. For example:

    INPUT: 1234
    OUTPUT: 0, 6, 1, 7

    INPUT: 1230
    OUTPUT: 0, 6

    INPUT: 12
    OUTPUT: 0, 6

    INPUT: 10
    OUTPUT: _____ (NOTHING), it doesn't even print the text in the printf statement

    Why would a case with 0's in it be any different for what I am doing here?

    Code:
    #include <stdio.h>
    #include <string.h>
    int main(){
    
    
    char array[256];
    fgets(array,255,stdin);
    
    
    int f;
    for(f=0;f<strlen(array)-1;f++){
    array[f] -= 48;
    }
    
    
    int i;
    
    
    int last_cell = strlen(array)-2;
    
    
    i = last_cell;
    
    
    for(i=last_cell ; i>=0; i--){
    
    
    int flag = 0;
    if( i != 0 && (array[i - 1] % 2) == 1)
    flag = 1;
    
    
    array[i] /= 2;
    if(flag == 1){
    array[i] += 5;
    }
    }
    
    
    int j;
    for(j=0;j<=last_cell;j++){
    printf("array[%d] == %d,",j,array[j]);
    
    
    }
    }
    Last edited by Salem; 04-10-2012 at 10:43 AM. Reason: Restored

  2. #2
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    I think the problem is that when I run the strlen function, it picks up the 0s as a "/0" null terminating character and thus errs in its measurement of the string. How else can I do this. I tried loading the input into the string with a for loop and getchar(), but that doesn't work because I don't know how many values the user will input so I have to loop 255 times to load a string that could be for four or five values.

    Also side question with regard to the previous point, since I already have your attention. Why is it that when I do a for loop to load a string of 256, say

    Code:
    for(i=0;i<256;i++) ;
    array[i] = getchar();
    if(getchar() == '\n') break;
    If I input a five character string, the command line doesn't return, it just stays there waiting, maybe expecting more output?

  3. #3
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    Why don't you turn the user input into an integer, do the arithmetic, and then turn it back to a character array?

  4. #4
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    Because I am trying to do this for arbitrarily long integers between 1 and 255. So that was my first plan of action, but at around 24 ints or so the long long int stops holding the conversion value accurately

    Unless that's not what you meant and if so please elaborate if you can.

  5. #5
    - - - - - - - - oogabooga's Avatar
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    Once you've subtracted '0' (or 48 as you call it) from all the elements, any that were '0' are now 0 so you can't use any string functions after that point since they interpret 0 as the end of the array. To fix it simply set a variable to the length of the array before modifying the data and use that variable instead of calling strlen.
    The cost of software maintenance increases with the square of the programmer's creativity. - Robert D. Bliss

  6. #6
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    NVM Fixed it. I simply moved the last_cell variable assignment up to before my loop converting the string ASCIIs into their decimal values. If anyone cares, haha

  7. #7
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    Haha, ooga, I swear I didn't read that before I did it but thanks any way. You are a wise fellow

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