help with nested loops

**geo_c** · 07-08-2004

Hello, I am new to c programming and am trying to write a simple program to get the following output:

ABCDE
ABCD
ABC
AB
A

The code I have written gives me an output of:

ABCDE
BCDE
CDE
DE
E

I can't seem to figure out how to change this output. I have played with the nested loop but still cannot figure out the problem. There must be a way to count down. Any help I can get is much appreciated. Thank you.

source code:
#include <stdio.h>
int main(void)
{
const int ROWS = 5;
const int CHARS = 5;
int row;
int ch;

for (row = 0; row < ROWS; row++)
{
for (ch = ('A' + row); ch < ('A' + CHARS); ch++)
printf("%c", ch);
printf("\n");
}
fflush(stdin);
getchar();
return 0;
}

**"%s", username** · 07-08-2004

for (ch = ('A' + row); ch < ('A' + CHARS); ch++)

I may not know everything about c, but if the value of the first character is 'A' plus the row it's on, wouldn't that row not start with an 'A'?

Maybe that'll help.

**quzah** · 07-08-2004

The poster needs to use [code] tags, otherwise most people don't even bother reading their posts. Just like they didn't bother reading the board's Announcements!

[edit]Line snipped. Still not awake.[/edit]

[edit2]Fun with only one loop...

Code:

void OxOO(char *OxO0,int Ox0O)
{
        char Ox00[0x1A]={0x00},Ox01;
        for( Ox0O=Ox0O%0x1A,Ox01=0x00;Ox01<Ox0O;Ox01=Ox01+0x01 )
        {
                strncpy( Ox00, OxO0+Ox01, Ox0O-Ox01 );
                (Ox0O-Ox01)[Ox00]=0x00;
                printf("%s\n",Ox00);
        }
}

Because we wouldn't want you to turn it in as-is for home work, now would we?

[/edit2]

Quzah.

**Devil Panther** · 07-08-2004

I guess you can always do this:

Code:

char str[]="ABCDE\0";
int i;

i = strlen(str);
while (i--) {
   printf("%s", str);
   str[i] = '\0';
}

**quzah** · 07-08-2004

Originally Posted by Devil Panther

I guess you can always do this:

Code:

char str[]="ABCDE\0";
int i;

i = strlen(str);
while (i--) {
   printf("%s", str);
   str[i] = '\0';
}

You proabably want to try that again, because the output of yours is:

ABCDEABCDABCABA

Of course, I misread the output they wanted, so mine gives the gradiated version:

ABC
BC
C

(Because I figured that would be the more challenging of the two, so that'd be what they wanted. Guess not.

)

Quzah.

**Devil Panther** · 07-08-2004

oops, forgot the \n

try this:

Code:

char str[]="ABCDE\0";
int i;

i = strlen(str);
while (i--) {
   printf("%s\n", str);
   str[i] = '\0';
}

**quzah** · 07-08-2004

You could also have just used puts.

Quzah.

**Devil Panther** · 07-08-2004

you always have to say the last word...

me too

**quzah** · 07-08-2004

Here's another fun one, just for grins...

Code:

void O_Oy( char *o_o, int o_O )
{
        char V_V [BUFSIZ]="%s\n";
        char T_T [BUFSIZ]="%%[^%s]";
        char v_v [BUFSIZ]={0};
        char x_x [BUFSIZ]={0};

        while( o_O -- )
        {
                sprintf( v_v, T_T, o_o + o_O + 1  );
                sscanf( o_o, v_v, x_x );
                printf( V_V, x_x );
        }
}

Because modifiable format specifiers are fun!

Quzah.

**sean** · 07-08-2004

Quzah - your code always reminds me of a MagicEye cartoon.

**viaxd** · 07-08-2004

and here's a recursive version for completeness

Code:

void foo(char *s, int n)
{
  int i;

  if (n >= 1)
  {
    for (i = 0; i < n; i++)
      printf("%c", s[i]);
    putchar('\n');

    foo(s, --n);
  }
}

**Meloshski** · 07-08-2004

Originally Posted by geo_c

for (row = 0; row < ROWS; row++)
{
for (ch = ('A' + row); ch < ('A' + CHARS); ch++)
printf("%c", ch);
printf("\n");
}

As %'s said that ch has to start at 'A' every time so adding row to it is bad. yet you want to have it only disply a diminishing number of letters each round.

If you read your for loop out
For Ch is A plus row(wich incrments up); stop the loop when ch is equal to 'A' + char(wich needs to incment down every loop); incment ch.

Any way,
I do have a question about the code from some of the more expeienced coders, what is the use of useing a constant integer there over a regular integer? And why do teachers and books tech fflush(stdin); when its um bad?

~Meloshski

**geo_c** · 07-08-2004

Thanks to all for all the suggestions! You have put me on the right track. Much appreciated.

Geo.

**Beast()** · 07-09-2004

Originally Posted by geo_c

Thanks to all for all the suggestions! You have put me on the right track. Much appreciated.

Geo.

With all the suggestions they gave you, they put you more than on track. They stuck a firecracker in your ass and made you lap the track.

I thought this would be a question I could handle, until I came in and saw it overkilled.

Haha, this forum is awesome.

**geo_c** · 07-11-2004

Yes, I said the right track.

for (stop_ch = 'E'; stop_ch >= 'A'; stop_ch--)
{
for (ch='A'; ch<=stop_ch; ch++)
{
printf("%c", ch);
}
printf("\n");

Thanks anyway.

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