Thread: assigning an string of arrays by loop

the idea is to assign an array of string, for example:

a[0] = a
a[1] = aa
a[2] = aaa
a[3] = aaaa
a[4] = aaaaa

but assigned and outputted in a for loop:

Code:

printf("%s\n", ba[i]);

at the moment, i have something like this

Code:

    char ba[10];


    char first[] = "first";
    char second[] = "second";



    for(i=0;i<10;i++){
        strcat(second,first);
            ba[i] = second;
            printf("%s\n", ba[i]);


  }

thanks =]

that outputs:

·⌂a
·⌂aa
·⌂aaa
·⌂aaaa
·⌂aaaaa
·⌂aaaaaa
·⌂aaaaaaa
·⌂aaaaaaaa
·⌂aaaaaaaaa
·⌂aaaaaaaaaa

Code:

char ba[10][12];
strcpy(ba[0],"a");
for(int i=0;i<10;i++) {
    strcpy(ba[i],ba[i-1]);
    strcat(ba[i],"a");
    printf("%s\n",ba[i]);
}

=]

a
aa
aaa
aaaa
aaaaa
aaaaaa
aaaaaaa
aaaaaaaa
aaaaaaaaa
aaaaaaaaaa

thanks for the code, seeing that it works is one thing, i would like to know how one of the code means, can someone explain this code for me?

Code:

strcpy(ba[i],ba[i-1]);

im a bit confused, are they both 'ba' array? the 10 and 12 one?

Originally Posted by WaterSerpentM

im a bit confused, are they both 'ba' array? the 10 and 12 one?

ba is a two dimensional array. 10 arrays of 12 chars each. Think in terms of a spreadsheet of 10 rows of 12 fields.

Why would you assume that?

"for(int i=0;i<10;i++)"

Wouldn't i be 0 the first time? In that case, what is i-1?

i-1 is before the start of the array!

soz i edited just before you posted

'ok so,

on the first loop the first i is 0 and the second i is -1

?'

Originally Posted by WaterSerpentM

soz i edited just before you posted

'ok so,

on the first loop the first i is 0 and the second i is -1

?'

Yes.

Normally, for loops are written as

Code:

for(int i = 0, i < 10; i++)

But in this case, you might write it as:

Code:

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

int main(void)
{

  char ba[10][12];
  strcpy(ba[0],"a");
  printf("%s\n",ba[0]);

  for(int i=1;i<10;i++)
  {
    strcpy(ba[i],ba[i-1]);
    strcat(ba[i],"a");
    printf("%s\n",ba[i]);
  }
    return 0;
}

btw the same thing happens without code 2