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Concatenating function not working right?

This is a discussion on Concatenating function not working right? within the C Programming forums, part of the General Programming Boards category; I have a function that concatenate the strings in an array(2D) Ex 1: Sean Connery Micheal King James Wood Result: ...

  1. #1
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    Concatenating function not working right?

    I have a function that concatenate the strings in an array(2D)
    Ex 1: Sean Connery Micheal King James Wood
    Result: SeanConnery MichealKing JamesWood ...
    The concatenation function working correctly and displays correctly in the function.
    But if I make another function to display it, it shows this

    Ex 2: SeanConnery Sean MichealKing Micheal JamesWood James..
    It adds to first name. Why?

    Code:
    void Concatenation( char dest[200][13] )
      {
          // loop through and concatenation the strings
        for(int i=0;i<200;i+=2)
         {
          myStrCat(dest[i],dest[i+1]); // mystrcat is equalto strcat()
          
          cout << dest[i] << " "; // display correctly Ex 1
         }
      
     }
    Code:
    void display(  char dest[200][13] ){
       // Initialize variables
       int i;
       
       for( i = 0; i < 208; i++ )
        {
          
          cout << dest[i] << " "; // display wrongly displays Ex2
        }
    }

  2. #2
    Registered User Suhasa010's Avatar
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    Quote Originally Posted by defjamvan View Post
    I have a function that concatenate the strings in an array(2D)
    Ex 1: Sean Connery Micheal King James Wood
    Result: SeanConnery MichealKing JamesWood ...
    The concatenation function working correctly and displays correctly in the function.
    But if I make another function to display it, it shows this

    Ex 2: SeanConnery Sean MichealKing Micheal JamesWood James..
    It adds to first name. Why?

    Code:
    void Concatenation( char dest[200][13] )
      {
          // loop through and concatenation the strings
        for(int i=0;i<200;i+=2)
         {
          myStrCat(dest[i],dest[i+1]); // mystrcat is equalto strcat()
          
          cout << dest[i] << " "; // display correctly Ex 1
         }
      
     }
    Code:
    void display(  char dest[200][13] ){
       // Initialize variables
       int i;
       
       for( i = 0; i < 208; i++ )
        {
          
          cout << dest[i] << " "; // display wrongly displays Ex2
        }
    }
    try declaring dest[200][13] globally or make it 'static'

  3. #3
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    Quote Originally Posted by Suhasa010 View Post
    try declaring dest[200][13] globally or make it 'static'
    Why?

    OP -- I ran your code with:
    Code:
       char dest[200][13] = {"Sean", "Connery", "Micheal", "King", "James", "Wood"};
    and got:
    Code:
    SeanConnery Connery MichealKing King JamesWood Wood
    So not quite the same as you but close enough.
    It looks like you're misunderstood what strcat() does. strcat(str1, str2) concatenates a copy of str2 onto the end of str1. It doesn't change str2 in any way. So assuming "MyStrCat" really is the same as strcat:
    Code:
       myStrCat(dest[i],dest[i+1]);
    If dest[i] contains "Sean" and dest[i+1] contains "Connery", then after the strcat, dest[i] will contain "SeanConnery" and dest[i+1] will still contain "Connery". So you need to either have i += 2 as your loop increment in display(), or you need to reorganise your array to exclude the single names. If that's what you want then you'll need to copy the full names down so they're in consecutive elements, and probably zero out the rest of the elements. I'm not sure what you're trying to do though, as you still have a 200 (well, 208, typo?) loop terminator in display.

  4. #4
    and the hat of wrongness Salem's Avatar
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    > cout << dest[i] << " "; // display correctly Ex 1
    You should try printing say
    cout << i << "=" << dest[i] << " "; // display correctly Ex 1

    Now do the same in your display function - print the subscript associated with each string.

    > for( i = 0; i < 208; i++ )
    Not overflowing the bounds of your array would be a good idea as well.
    vart likes this.
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  5. #5
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    It works! Thanks smokeyangel. I just had to output i+=2. One more thing, If I wanted to only concatenate the first 4 string and leave the last two alone how would i do it?
    Result: SeanConnery MichealKing James Wood. ie, "James" and "Wood" are left concatenate but they are still included in the output. so i < 200 doesn't change.

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