Transpose a matrix giving me error when column>row-CodePudding

i want to transpose matrix the code works when column=row and when column>row but when row > column i get wrong answers

all of the code :

#include <stdio.h>
#include <stdlib.h>


 int main() {int row,column,tmp;
    scanf("%d",&row);
    scanf("%d",&column);
 int *image=(int*)malloc(sizeof(int)*row*column);
     int *target=(int*)malloc(sizeof(int)*row*column);
     for(int i=0;i<row;i  ){
         for(int j=0;j<column;j  ){
             scanf("%d",&tmp);
             image[i*column j]=target[i*column j]=tmp;
         }
     }
   transpose(row,column,target,image);
for (int i = 0; i< m; i  ) {
    for (int j = 0; j < n; j  )
        printf("%d\t", target[i*column j]);
    printf("\n");
}}
void transpose(int row, int column,int* target,int* image) {
    
        for (int i = 0; i < row; i  ) {
            for (int j = 0; j < column; j  ) {
                target[j * column   i] = image[i * column   j];
            }
        }
    
    }

my matrix in the image and i want to the transpose in the target .

input : 
1   2
3   4
5   6

output(what i get from my code) :
1   3   5   
5   4   6   
output (what should i get ) :

1   3   5
2   4   6

input work : 
1 2 3 
4 5 6
output : 
1 4
2 5
3 6

CodePudding user response：

As @Bob_ suggests, you are mis-calculating the offset into your target array.

Your source image has column columns and row rows; but the transposed image as row columns and column rows! (By the way - that's a poor choice of identifiers; consider num_columns and num_rows as parameters to the transpose function). So I believe you need to have:

target[j * row   i] = image[i * column   j];

in your inner loop.

CodePudding user response：

To understand what you are doing, I recommend you to print index value computed in you algorithm.
The problem is that i can be greater than column (same thing with j and row). You have to use % to improve your code.