sorting a matrix using column sort - c

Question

according to the book "introduction to algorithms I tried sorting a matrix using column sort.here is my approach
1) sort each row of matrix -
#include<stdio.h>
#include<stdlib.h>
void sort(int arr[3][3], int k)// here k defines the column number ,k remains constant through out the function
//because we have to sort the matrix column wise respectively
{
int i;
int c[10]={0};
int b[3][3];
for(i=0;i<3;i++)
{ c[arr[i][k]]++;
}
for(i=1;i<3;i++)
{
c[i]+=c[i-1];
}
for(i=2;i>=0;i--)
{
b[c[arr[i][k]]-1][k]=arr[i][k];
c[arr[i][k]]--;
}
for(i=0;i<3;i++)
{
arr[i][k]=b[i][k];
}
}
I have passed k as an argument,which is the column number (as it remains constant throughout the sorting of each column, and only the row number changes,so i have iterated only over the row number )
the function to pass the desired column number which then calls the count function
void column(int arr[3][3]) // to call the function column wise by passing k as a parameter to count function
{
int k;
for(k=0;k<3;k++)
sort(arr,k);
}
2) transpose a matrix
{
int i,j,temp;
for(i=0;i<3;i++)
{ for(j=0;j<3;j++)
temp=arr[i][j];
arr[i][j]=arr[j][i];
arr[j][i]=temp;
}
}
the print function
void print(int arr[3][3]) // to print the output
{
int i,j;
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
printf("%d ",arr[i][j]);
}
printf("\n");
}
}
the main function
{
int arr[3][3];
int i,j;
for (i=0;i<3;i++)
{
for(j=0;j<3;j++)
scanf("%d ",&arr[i][j]);
}
// prints the array just inputed
print(arr);
// column calls the function sort according to the column
column(arr);
transpose(arr); // matrix is transposed
printf("\n");
print(arr); // matrix is printed
column(arr); // matrix is again passed with respect to the columns and sorted
transpose(arr); // matrix is transposed to get the original matrix
printf("\n");
print(arr); //final result is printed
return 0;
}
the output is very unlikely how can it be sorted correctly

Answer 1

Here is a working version of your code. I fixed the dropped bracket and the transpose function:
#include <stdio.h>
#include<stdlib.h>
void sort(int arr[3][3], int k)// here k defines the column number ,k remains constant through out the function
//because we have to sort the matrix column wise respectively
{
int i,j;
int tmp = 0;
for(i=0;i<2;i++)
{
for (j = 0; j < 3-i-1; j++)
{
if (arr[j][k] > arr[j+1][k])
{
tmp = arr[j][k];
arr[j][k] = arr[j+1][k];
arr[j+1][k] = tmp;
}
}
}
printf("\n");
}
void column(int arr[3][3]) // to call the function column wise by passing k as a parameter to count function
{
int k;
for(k=0;k<3;k++)
{
sort(arr,k);
}
}
void transpose(int arr[3][3])
{
int i,j,temp;
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
if(i != j && i<j)
{
temp=arr[i][j];
arr[i][j]=arr[j][i];
arr[j][i]=temp;
}
}
}
}
void print(int arr[3][3]) // to print the output
{
int i,j;
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
printf("%d ",arr[i][j]);
}
printf("\n");
}
}
int main()
{
int arr[3][3] = {0};
int i,j;
for (i=0;i<3;i++)
{
for(j=0;j<3;j++)
scanf("%d ",&arr[i][j]);
}
printf("\n");
// prints the array just inputed
print(arr);
printf("\n");
// column calls the function sort according to the column
column(arr);
print(arr);
transpose(arr); // matrix is transposed
printf("\n");
print(arr); // matrix is printed
column(arr); // matrix is again passed with respect to the columns and sorted
printf("\n");
print(arr); // matrix is printed
transpose(arr); // matrix is transposed to get the original matrix
printf("\n");
print(arr); //final result is printed
return 0;
}
Here is the output of: Sort, Transpose, Sort, then transpose: