Thread: assigning an string of arrays by loop

Originally Posted by WaterSerpentM

btw the same thing happens without code 2

Did you run my version?

Print the first array before the for() loop, then run the loop starting with the second array.

i did run it

whats the point of printing before the loop?

Originally Posted by WaterSerpentM

i did run it

whats the point of printing before the loop?

The first line before the loop prints:
a

Then in the loop, it prints the remainder of the arrays, correctly:
aa
aaa
aaaa
aaaaa
aaaaaa
aaaaaaa
aaaaaaaa
aaaaaaaaa
aaaaaaaaaa

so

array[0] starts off as nothing, then strcat to 'a'
then with strcpy, array[1] becomes 'a', then strcat to 'aa', and so on

?

Originally Posted by WaterSerpentM

so

array[0] starts off as nothing, then strcat to 'a'
then with strcpy, array[1] becomes 'a', then strcat to 'aa', and so on

?

It should be quite obvious with the code and the results:

array[0] is set to "a" using strcpy()
print array[0]

for() loop:
strcpy() is used to copy from arrray[0] to array[1]
then strcat() is used to append "a" to array[1]
print array[1]
etc...

yup I get it entirely =]

WaterSerpentM:

The following is an alternative method for displaying what you wanted. It eliminates the need for both strcpy(), and strcat() functions!

Study it carefully.

Code:

#include <stdio.h>
// string.h no longer needed!

int main(void)
{
  // The line below will initialize the first array, ba[0] to "a"
  // and initialize all other bytes to Nul bytes ('\0')
  char ba[10][12] = {{"a"}};
  int x = 0;

  printf("%s\n",ba[0]);     // Print first array

  for(int i = 1;i < 10;i++) // For each of the remaining arrays
  {
    for(x = 0; x <= i; x++) // For each 'a' in the array
    {
      ba[i][x] = 'a';
    }

    // The following line is actually redundent, as all the
    // other bytes were Nulled.  But I would allways use it
    // to assure the string is Null terminated, in case the
    // ba array is reused later!
    ba[i][x] = '\0';

    printf("%s\n",ba[i]);   // Print next array
  }

  return 0;
}

check this out =]

Code:

#include <stdio.h>
#include <string.h>


int main() {





    char chara[10][10];
    int i;


    for(i=0;i<10;i++){
        strcpy(chara[i],chara[i-1]);
        strcat(chara[i],"a");
    }


    for(i=9;i>-1;i--){
    printf("%s\n",chara[i]);
    }


    return 0;
}

Code:

for(i=0;i<10;i++){
    strcpy(chara[i],chara[i-1]);
    strcat(chara[i],"a");
}

The first time through the loop, i == 0, and i - 1 IS -1!!!

I don't understand how this works! It is wrong and at some point it will fail!

Code:

for(i=9;i>-1;i--){
  printf("%s\n",chara[i]);
}

Better:

Code:

for(i=9;i >= 0;i--){
  printf("%s\n",chara[i]);
}

it works, it outputs:

aaaaaaaaaa
aaaaaaaaa
aaaaaaaa
aaaaaaa
aaaaaa
aaaaa
aaaa
aaa
aa
a

Originally Posted by WaterSerpentM

it works, it outputs:

aaaaaaaaaa
aaaaaaaaa
aaaaaaaa
aaaaaaa
aaaaaa
aaaaa
aaaa
aaa
aa
a

It may seem to work, but you are accessing an array OUTSIDE of the defined array!!!

chara[-1] WRONG!!!!!

I gave you two different solutions that work, but you keep going back to code that is wrong!

that was salem's coding originally,

and it looks more construct than yours

Originally Posted by WaterSerpentM

that was salem's coding originally,

and it looks more construct than yours

Salem's code was wrong. She admitted it. I don't know what you mean by "looks more construct".