Hi all,
1st time poster.

I have a fairly simple task that I need to carry out, however I am not terribly good at C programming, so bare with me!!!!
Basically I need to take in a string of 15 binary bits, from this input I will be adding bits 1,6,11 bits 2,7,12 bits 3,8,13 bits 4,9,14 and bits 5,10,15.
These will all give me parity which will either be a 0 or a 1. I then have to output the original 15 bits along with the 5 new bits, so my output will be 20 bits long.

I hope that all makes sense.......so far I have been trying to do it as such........
Code:
#include <stdio.h>
#include <string.h>
#include <math.h>

int main()
{
int codeword_array[20];
int i=0;

printf("Welcome to the 5-bit parity code calculator\nPlease enter the 1st bit of the 15 bit codeword now: \n");

for (int i>=0; i<16; i++)
{
int bit_array[i];
scanf("%d", bit_array[i])
if bit !=(0||1)
{
printf("All bits must be 0 or a 1");
}
codeword_array[i] = bit[i];
}

if (bit_array[0] + bit_array[5] + bit_array[10] = (0||2))
{
codeword_array[15] = 0;
}
else if (bit_array[0] + bit_array[5] + bit_array[10] = (1||3))
{
codeword_array[15] = 1;
}
else
{
printf("Error\n");
}
system("pause");
return 0;
}
The thinking behind this is that if I use a 20 bit array, and start off filling the 1st 15 blocks, then do the parity check on them and with my answers fill the final 5.
However I am getting a good few errors on this.

Hope someone can help.

Regards,

Niall.

2. Firt of all you should use == in your if statements. = is an assignment operator which means all your if tests will be true.

3. You also use "bit" but never declare it anywhere...

What errors are you getting?

4. Code:
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ')' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : warning C4552: '<' : operator has no effect; expected operator with side-effect
(14) : error C2059: syntax error : ')'
(15) : error C2143: syntax error : missing ';' before '{'
(16) : error C2057: expected constant expression
(16) : error C2466: cannot allocate an array of constant size 0
(16) : error C2133: 'bit_array' : unknown size
(18) : error C2143: syntax error : missing ';' before 'if'
(18) : error C2061: syntax error : identifier 'bit'
(22) : error C2109: subscript requires array or pointer type
(25) : error C2059: syntax error : 'if'
(29) : error C2059: syntax error : 'else'
(33) : error C2059: syntax error : 'else'
(39) : error C2143: syntax error : missing ')' before 'string'
(39) : error C2143: syntax error : missing '{' before 'string'
(39) : error C2059: syntax error : '<Unknown>'
(39) : error C2059: syntax error : ')'
(40) : error C2059: syntax error : 'return'
(41) : error C2059: syntax error : '}'
These are all the errors, (after I changed the = to == and declared bit) A lot of them seem to be linked to the one thing, so I think I might just be missing something simple thats causing a lot of them!!!

P.s. I declared bit outside the for loop, is this correct?

Code:
int codeword_array[20];
int i=0;
int bit;

printf("Welcome to the 5-bit parity code calculator\nPlease enter the 1st bit of the 15 bit codeword now: \n");

for (int i>=0; i<16; i++)

5. you need to use a & before bit_array[i] in your scanf statement.

And you need a ; after the scanf line too.

compile again and post your errors.

6. Ok, that got rid of a couple, thanks for that. The next one's are:

Code:
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ')' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : warning C4552: '<' : operator has no effect; expected operator with side-effect
(14) : error C2059: syntax error : ')'
(15) : error C2143: syntax error : missing ';' before '{'
(16) : error C2057: expected constant expression
(16) : error C2466: cannot allocate an array of constant size 0
(16) : error C2133: 'bit_array' : unknown size
(18) : error C2061: syntax error : identifier 'bit'
(22) : error C2109: subscript requires array or pointer type
(25) : error C2059: syntax error : 'if'
(29) : error C2059: syntax error : 'else'
(33) : error C2059: syntax error : 'else'
(39) : error C2143: syntax error : missing ')' before 'string'
(39) : error C2143: syntax error : missing '{' before 'string'
(39) : error C2059: syntax error : '<Unknown>'
(39) : error C2059: syntax error : ')'
(40) : error C2059: syntax error : 'return'
(41) : error C2059: syntax error : '}'
There seems to be a good few on line 14. Line 14 is the beginning of the for loop,
Code:
	for (int i>=0; i<16; i++)

7. the fist part of the for statement sets the intial value of i.

for (int i = 0; i<16; i++) will loop from 0 - 15

8. Ok, thats grand thanks,

But still giving the errors that i'm missing ;'s around line 14. Dunno where this is happening though,

Any ideas?

10. Code:
#include <stdio.h>
#include <string.h>
#include <math.h>

int main()
{

int codeword_array[20];
int i=0;
int bit;

printf("Welcome to the 5-bit parity code calculator\nPlease enter the 1st bit of the 15 bit codeword now: \n");

for (int i = 0; i<16; i++)
{
int bit_array[i];
scanf("%d", &bit_array[i]);
if bit !==(0||1)
{
printf("All bits must be 0 or a 1");
}
codeword_array[i] = bit[i];
}

if (bit_array[0] + bit_array[5] + bit_array[10] == (0||2))
{
codeword_array[15] == 0;
}
else if (bit_array[0] + bit_array[5] + bit_array[10] == (1||3))
{
codeword_array[15] == 1;
}
else
{
printf("Error\n");
}

system("pause");
return 0;
}

11. You can't declare bit_array inside the for loop. Doing so will declare it each iteration.

12. You test bit after the scanf, but never assign bit a value. You should do...

Code:
scanf("%d", &bit);
if (bit != 0 && bit !=1)
{
printf("All bits...");
}
else
{
codeword_array[i] = bit;
}
You don't need bit_array at all. Change bit_array in your subsequent if statements to codeword_array.

13. Ok, should it be declared globally? I have done it like this now....
Code:
int codeword_array[20];
int i=0;
int bit;
int bit_array[i];

printf("Welcome to the 5-bit parity code calculator\nPlease enter the 1st bit of the 15 bit codeword now: \n");

for (int i = 0; i<16; i++)
{
scanf("%d", &bit_array[i]);
if bit !==(0||1)
{
printf("All bits must be 0 or a 1");
}
codeword_array[i] = bit[i];
}

if (bit_array[0] + bit_array[5] + bit_array[10] == (0||2))
{
codeword_array[15] == 0;
}
else if (bit_array[0] + bit_array[5] + bit_array[10] == (1||3))
{
codeword_array[15] == 1;
}
else
{
printf("Error\n");
}

system("pause");
return 0;
}
With some new errors

Code:
(11) : error C2057: expected constant expression
(11) : error C2466: cannot allocate an array of constant size 0
(11) : error C2133: 'bit_array' : unknown size
(15) : error C2143: syntax error : missing ';' before 'type'
(15) : error C2143: syntax error : missing ';' before 'type'
(15) : error C2143: syntax error : missing ')' before 'type'
(15) : error C2143: syntax error : missing ';' before 'type'
(15) : warning C4552: '<' : operator has no effect; expected operator with side-effect
(15) : error C2059: syntax error : ')'
(16) : error C2143: syntax error : missing ';' before '{'
(18) : error C2061: syntax error : identifier 'bit'
(22) : error C2109: subscript requires array or pointer type
(25) : error C2059: syntax error : 'if'
(29) : error C2059: syntax error : 'else'
(33) : error C2059: syntax error : 'else'
(39) : error C2143: syntax error : missing ')' before 'string'
(39) : error C2143: syntax error : missing '{' before 'string'
(39) : error C2059: syntax error : '<Unknown>'
(39) : error C2059: syntax error : ')'
(40) : error C2059: syntax error : 'return'
(41) : error C2059: syntax error : '}'

14. Ok, had posted that last one before I realised there was a reply!!!!

Changing bit_array to codeword_array worked for a lot of them, down to 7 errors now.
code is
Code:
#include <stdio.h>
#include <string.h>
#include <math.h>

int main()
{

int codeword_array[20];
int i=0;
int bit;

printf("Welcome to the 5-bit parity code calculator\nPlease enter the 1st bit of the 15 bit codeword now: \n");

for (int i = 0; i<16; i++)
{
scanf("%d", &bit);
if (bit != 0 && bit !=1)
{
printf("All bits must be a 0 or a 1/n");
}
else
{
codeword_array[i] = bit;
}

if (codeword_array[0] + codeword_array[5] + codeword_array[10] == (0||2))
{
codeword_array[15] = 0;
}
else if (codeword_array[0] + codeword_array[5] + codeword_array[10] == (1||3))
{
codeword_array[15] = 1;
}
else
{
printf("Error\n");
}

system("pause");
return 0;
}

/*scanf( "%d", &bit1 );

if ( bit1 != (0 || 1))
{
printf( "All bits must be either 0 or 1\n" );
}
else
{
printf( "You entered %d", bit1);
}
and the remaining errors are

Code:
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : error C2143: syntax error : missing ')' before 'type'
(14) : error C2143: syntax error : missing ';' before 'type'
(14) : warning C4552: '<' : operator has no effect; expected operator with side-effect
(14) : error C2059: syntax error : ')'
(15) : error C2143: syntax error : missing ';' before '{'
(43) : warning C4013: 'system' undefined; assuming extern returning int
(94) : fatal error C1075: end of file found before the left brace '{' at 'c:\users\niall\documents\college\4th year\2nd semester\ee402\5bit parity code\5bit parity code\source.c(6)' was matched

15. You don't need bit_array at all. If you're storing the bit array in codeword_array, why store it in bit_array too?

and you can't use [i] in the declaration.