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Counting numbers in an array

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andyg55

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Counting numbers in an array

Feb 1st, 2008

Hi guys,

I have an array which reads in a file and displays it to the screen. The output is as follows:

1 0 0
2 0 0
3 0 0
4 1 2
5 1 2
6 0 0
7 3 4
8 5 6
9 7 8
10 7 8

I then used a random number generator to add a 1 or a 0 to a further 2 columns in the array. An example of an output is as follows:

1 0 0 1 0
2 0 0 0 1
3 0 0 1 1
4 1 2 1 0
5 1 2 0 1
6 0 0 1 1
7 3 4 1 1
8 5 6 1 1
9 7 8 1 0
10 7 8 0 1

I was wondering if anyone knew how to count the 1's and 0's I have in the 4th and 5th columns? For the above example, below the output of the array, I would like it to print the following to the screen:

Number of 0's present: 6
Number of 1's present: 14

I'm struggling with the code. Does anyone have any ideas? My current code is:

 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>
 
int j;
int matrix[100][5] = {0};
int numCols = 3;
int numRows = 0;
float rand1, rand2, rand3, rand4;
void SetSeed();
 
int main () {
 
const float RANGE = 1.0;
SetSeed();
 
ifstream inFile;
inFile.open("input.txt");
 
  if (!inFile)
  {
  printf ("Unable to open input file");
  exit(1);
  }
 
while (inFile >> matrix[numRows][0])
{
printf ("%d\t", matrix[numRows][0]);
for (j = 1; j < numCols; j++)
{
inFile >> matrix[numRows][j];
printf ("%d\t", matrix[numRows][j]);
}
 
int counter;
 
if (matrix[numRows][1] == 0 && matrix[numRows][2] == 0){
   for (counter = 1;counter <= 1;counter++){
   rand1 = (float) rand() * RANGE / RAND_MAX;
   rand2 = (float) rand() * RANGE / RAND_MAX;
   }
   if (rand1 < 0.4){
   matrix[numRows][3] = 0;
   printf("\t%d", matrix[numRows][3]);
   }   
   if (rand1 >= 0.4){
   matrix[numRows][3] = 1;
   printf("\t%d", matrix[numRows][3]);
   }      
   if (rand2 < 0.4){
   matrix[numRows][4] = 0;
   printf("\t%d", matrix[numRows][4]);
   }      
   if (rand2 >= 0.4){
   matrix[numRows][4] = 1;
   printf("\t%d", matrix[numRows][4]);
   }
   }
 
else{
 
   for (counter = 1;counter <= 1;counter++){
   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;
   }
   if (rand3 < 0.5){
   matrix[numRows][3] = 0;
   printf("\t%d", matrix[numRows][3]);
   }   
   if (rand3 >= 0.5){
   matrix[numRows][3] = 1;
   printf("\t%d", matrix[numRows][3]);
   }      
   if (rand4 < 0.5){
   matrix[numRows][4] = 0;
   printf("\t%d", matrix[numRows][4]);
   }      
   if (rand4 >= 0.5){
   matrix[numRows][4] = 1;
   printf("\t%d", matrix[numRows][4]);
   }
   }
 
 
 
numRows++;
printf ("\n");
}
 
inFile.close ();
}
 
void SetSeed() {
 
FILE *seed_file;
long int seed_value;
 
seed_file = fopen("seed.txt","r");
fscanf(seed_file,"%d",&seed_value);
fclose(seed_file);
srand(seed_value);
seed_file = fopen("seed.txt","w");
fprintf(seed_file,"%d",rand());
fclose(seed_file);
}
#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>

int j;
int matrix[100][5] = {0};
int numCols = 3;
int numRows = 0;
float rand1, rand2, rand3, rand4;
void SetSeed();

int main () {

const float RANGE = 1.0;
SetSeed();

ifstream inFile;
inFile.open("input.txt");

  if (!inFile)
  {
  printf ("Unable to open input file");
  exit(1);
  }

while (inFile >> matrix[numRows][0])
{
printf ("%d\t", matrix[numRows][0]);
for (j = 1; j < numCols; j++)
{
inFile >> matrix[numRows][j];
printf ("%d\t", matrix[numRows][j]);
}

int counter;

if (matrix[numRows][1] == 0 && matrix[numRows][2] == 0){
   for (counter = 1;counter <= 1;counter++){
   rand1 = (float) rand() * RANGE / RAND_MAX;
   rand2 = (float) rand() * RANGE / RAND_MAX;
   }
   if (rand1 < 0.4){
   matrix[numRows][3] = 0;
   printf("\t%d", matrix[numRows][3]);
   }   
   if (rand1 >= 0.4){
   matrix[numRows][3] = 1;
   printf("\t%d", matrix[numRows][3]);
   }      
   if (rand2 < 0.4){
   matrix[numRows][4] = 0;
   printf("\t%d", matrix[numRows][4]);
   }      
   if (rand2 >= 0.4){
   matrix[numRows][4] = 1;
   printf("\t%d", matrix[numRows][4]);
   }
   }

else{
   
   for (counter = 1;counter <= 1;counter++){
   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;
   }
   if (rand3 < 0.5){
   matrix[numRows][3] = 0;
   printf("\t%d", matrix[numRows][3]);
   }   
   if (rand3 >= 0.5){
   matrix[numRows][3] = 1;
   printf("\t%d", matrix[numRows][3]);
   }      
   if (rand4 < 0.5){
   matrix[numRows][4] = 0;
   printf("\t%d", matrix[numRows][4]);
   }      
   if (rand4 >= 0.5){
   matrix[numRows][4] = 1;
   printf("\t%d", matrix[numRows][4]);
   }
   }
   
   
    
numRows++;
printf ("\n");
}

inFile.close ();
}

void SetSeed() {

FILE *seed_file;
long int seed_value;

seed_file = fopen("seed.txt","r");
fscanf(seed_file,"%d",&seed_value);
fclose(seed_file);
srand(seed_value);
seed_file = fopen("seed.txt","w");
fprintf(seed_file,"%d",rand());
fclose(seed_file);
}

Thanks for any help you can give me

Last edited by Ancient Dragon; Feb 1st, 2008 at 8:17 pm. Reason: add line numbers for easier referencing

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Re: Counting numbers in an array

Feb 1st, 2008

delete lines 38 and 41 because tha loop only executes once, so there is no point to having a loop there.

line 41: just make it a simple else statement. If the value is not < 0.4 then there is only one other choice, That whole loop can be simplified to this:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
if (matrix[numRows][1] == 0 && matrix[numRows][2] == 0){
   rand1 = (float) rand() * RANGE / RAND_MAX;
   rand2 = (float) rand() * RANGE / RAND_MAX;
   if (rand1 < 0.4){
   matrix[numRows][3] = 0;
   }   
   else{
   matrix[numRows][3] = 1;
   }      
   printf("\t%d", matrix[numRows][3]);
 
   if (rand2 < 0.4){
   matrix[numRows][4] = 0;
   }      
   else{
   matrix[numRows][4] = 1;
   }
   printf("\t%d", matrix[numRows][4]);
   }
 
else{
 
   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;
 
   if (rand3 < 0.5){
   matrix[numRows][3] = 0;
   }   
   else{
   matrix[numRows][3] = 1;
   }      
   printf("\t%d", matrix[numRows][3]);
 
   if (rand4 < 0.5){
   matrix[numRows][4] = 0;
   }      
   else{
   matrix[numRows][4] = 1;
   }
   printf("\t%d", matrix[numRows][4]);
   }
if (matrix[numRows][1] == 0 && matrix[numRows][2] == 0){
   rand1 = (float) rand() * RANGE / RAND_MAX;
   rand2 = (float) rand() * RANGE / RAND_MAX;
   if (rand1 < 0.4){
   matrix[numRows][3] = 0;
   }   
   else{
   matrix[numRows][3] = 1;
   }      
   printf("\t%d", matrix[numRows][3]);

   if (rand2 < 0.4){
   matrix[numRows][4] = 0;
   }      
   else{
   matrix[numRows][4] = 1;
   }
   printf("\t%d", matrix[numRows][4]);
   }

else{
   
   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;

   if (rand3 < 0.5){
   matrix[numRows][3] = 0;
   }   
   else{
   matrix[numRows][3] = 1;
   }      
   printf("\t%d", matrix[numRows][3]);

   if (rand4 < 0.5){
   matrix[numRows][4] = 0;
   }      
   else{
   matrix[numRows][4] = 1;
   }
   printf("\t%d", matrix[numRows][4]);
   }

numRows++;
printf ("\n");
}
[/code]

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andyg55

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Re: Counting numbers in an array

Feb 1st, 2008

Cheers for that mate, my code looks a bit neater now and it makes more sense.

Do you have any tips for the counting question though?

Any help is welcomed, thanks!

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Re: Counting numbers in an array

Feb 1st, 2008

one way is to use another matrix

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int counters[2] = {0}
 
for(int i = 0; i < numRows; ++i)
{
   counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
   counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}
int counters[2] = {0}

for(int i = 0; i < numRows; ++i)
{
   counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
   counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}

The above uses the 0 or 1 in the matrix column to index into the counters array.

Last edited by Ancient Dragon; Feb 1st, 2008 at 8:39 pm.

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Re: Counting numbers in an array

Feb 1st, 2008

Ok, I'm thinking of placing the int counters[2]={0} at the top of my code as a global variable, and placing the code below it at line 89. Would this be appropriate placement? Or would you put them in all together at a different line?

I'm very unsure as to how to get the program to print out the results of the count? Do you have any tips?

Thanks.

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Re: Counting numbers in an array

Feb 1st, 2008

>>I'm very unsure as to how to get the program to print out the results of the count? Do you have any tips?

Yes -- do it similar to how you did the other printf() lines

As for your first question -- give it your best shot and test your program to see if it works. If it doesn't work then try something else. Find out what kinds of solution(s) you can come up with.

Don't PM me with questions -- you might get a nasty PM in response. If you have a question then post it in one of the forums.

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andyg55

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Re: Counting numbers in an array

Feb 1st, 2008

Ok I'm really struggling with positioning, sorry.

I've placed the variable globally, and then placed the code as follows:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
while (inFile >> matrix[numRows][0])
{
printf ("%d\t", matrix[numRows][0]);
for (j = 1; j < numCols; j++)
{
inFile >> matrix[numRows][j];
printf ("%d\t", matrix[numRows][j]);
}
 
for(int i = 0; i < numRows; ++i)
{
counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}
 
int counter;
while (inFile >> matrix[numRows][0])
{
printf ("%d\t", matrix[numRows][0]);
for (j = 1; j < numCols; j++)
{
inFile >> matrix[numRows][j];
printf ("%d\t", matrix[numRows][j]);
}

for(int i = 0; i < numRows; ++i)
{
counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}

int counter;

I get 3 error messages:
1. Keyword 'int' cannot be declared as a variable
2. Terminating semicolon missing
3. 'numCols' has not been declared

However, none of these make sense. Hmm, I have tried, but I just can't get it?

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Re: Counting numbers in an array

Feb 1st, 2008

your compiler should tell what lines they were on.
the first two are simple syntax errors
Perhaps the 'int' keyword problem is related to the undeclared variable 'numCols' where you ment to write:

int numCols;

but wrote

int int

which would give those exact three.

Do a string search on your code for int.

"I like beating by head against the wall because it feels so good when I stop"

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Re: Counting numbers in an array

Feb 1st, 2008

•

Originally Posted by andyg55

Ok I'm really struggling with positioning, sorry.

I've placed the variable globally, and then placed the code as follows:
Help with Code Tags

C++ Syntax (Toggle Plain Text)
while (inFile >> matrix[numRows][0])
{
printf ("%d\t", matrix[numRows][0]);
for (j = 1; j < numCols; j++)
{
inFile >> matrix[numRows][j];
printf ("%d\t", matrix[numRows][j]);
}
 
for(int i = 0; i < numRows; ++i)
{
counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}
 
int counter;
while (inFile >> matrix[numRows][0]) { printf ("%d\t", matrix[numRows][0]); for (j = 1; j < numCols; j++) { inFile >> matrix[numRows][j]; printf ("%d\t", matrix[numRows][j]); } for(int i = 0; i < numRows; ++i) { counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column } int counter;
I get 3 error messages:
1. Keyword 'int' cannot be declared as a variable
2. Terminating semicolon missing
3. 'numCols' has not been declared

However, none of these make sense. Hmm, I have tried, but I just can't get it?

1) counting the number of 0s and 1s can not be done until after the entire file has been read in and after the 4th and 5th columns have been completed. You put the cart before the horse.

2) int counter; What is that?

Last edited by Ancient Dragon; Feb 1st, 2008 at 10:09 pm.

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Re: Counting numbers in an array

#10

Feb 1st, 2008

sorry yes, I got rid of int counter;

Forget that!

I placed the code as follows:

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else{
   int dad = matrix[i][1];    // 1 is "dad" column
   int mom = matrix[i][2];   // 2 is "mom" column
 
   int dadRowIndex = dad - 1;
   int momRowIndex = mom -1;
 
   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;
 
   if (rand3 < 0.5){
   matrix[i][3] = matrix[dadRowIndex][3];
   }   
   else{
   matrix[i][3] = matrix[dadRowIndex][4];
   }
   printf("\t%d", matrix[i][3]);
 
   if (rand4 < 0.5){
   matrix[i][4] = matrix[momRowIndex][3];
   }
   else{
   matrix[i][4] = matrix[momRowIndex][4];
   }
   printf("\t%d", matrix[i][4]);
}
 
i++;
printf ("\n");
}
 
for(int i = 0; i < i; ++i)
{
counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}
 
 
inFile.close ();
}
else{
   int dad = matrix[i][1];    // 1 is "dad" column
   int mom = matrix[i][2];   // 2 is "mom" column

   int dadRowIndex = dad - 1;
   int momRowIndex = mom -1;

   rand3 = (float) rand() * RANGE / RAND_MAX;
   rand4 = (float) rand() * RANGE / RAND_MAX;

   if (rand3 < 0.5){
   matrix[i][3] = matrix[dadRowIndex][3];
   }   
   else{
   matrix[i][3] = matrix[dadRowIndex][4];
   }
   printf("\t%d", matrix[i][3]);
      
   if (rand4 < 0.5){
   matrix[i][4] = matrix[momRowIndex][3];
   }
   else{
   matrix[i][4] = matrix[momRowIndex][4];
   }
   printf("\t%d", matrix[i][4]);
}

i++;
printf ("\n");
}

for(int i = 0; i < i; ++i)
{
counters[ matrix[i][3] ]++; // count the number of 0s or 1s in the 4th column
counters[ matrix[i][4] ]++; // count the number of 0s or 1s in the 5th column
}


inFile.close ();
}

My program seems to run fine!! However, there is obviously no count being printed to screen.

Would I go something like:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
printf("counters[ matrix[i][3] ]")
printf("counters[ matrix[i][4] ]")
printf("counters[ matrix[i][3] ]")
printf("counters[ matrix[i][4] ]")

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
printf("counters[ matrix[i][3] ]++")
printf("counters[ matrix[i][4] ]++")
printf("counters[ matrix[i][3] ]++")
printf("counters[ matrix[i][4] ]++")