passing arguments from incompatible pointer type ,warning in the function call Transpose in the main routine.

[ravi123]

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

int size_b_row1;
int size_b_col1;


int main(void) {

double C[4][4] = {{1,3,5,2},{7,6,2,2},{1,2,7,3},{2,3,5,3}};
double TC[4][4];

transpose(C, TC);

puts("Hello World"); /* prints Hello World */
return EXIT_SUCCESS;
}


void transpose(double** matrix_t, double** matrix)
{

int i,j;

/* allocate memory for matrix */

matrix_t=(double **) malloc(sizeof(double *)*size_b_row1);
for( i=0;i<size_b_row1;i++)
{
matrix_t[i]=(double *) malloc(sizeof(double*)*size_b_col1);
}

matrix=(double **) malloc(sizeof(double *)*size_b_row1);
for( i=0;i<size_b_row1;i++)
{
matrix[i]=(double *) malloc(sizeof(double*)*size_b_col1);
}

//output matrix

for(i=0;i<size_b_col1;i++)
{
for(j=0;j<size_b_row1;j++)
{
matrix_t[j][i]= matrix[i][j];
}

}

//free memory
for(i=0;i<size_b_row1;i++)
{
free(matrix[i]);
}
free(matrix);


for(i=0;i<size_b_row1;i++)
{
free(matrix_t[i]);
}
free(matrix_t);
} // end of main body

[MiiNiPaa]

It is array of arrays, not array of pointers to another arrays.
Arrays are not a pointers. Stack-based multidimensionals arrays are evil. Now you know why.

EDIT: if you have C++11 compiler, following will work:

double** C = new double*[4]{new double[4]{1,3,5,2}, new double[4]{7,6,2,2},
                            new double[4]{1,2,7,3}, new double[4]{2,3,5,3}};
double** TC = new double*[4]{new double[4], new double[4],
                             new double[4], new double[4]};

But you will have memory leak in your transpose function.

EDIT2:: WTF transpose function does? It doesn't even using passed parameters. It uses C-style memory manipulation (discouraged in C++) and on top of that has undefined behavior due to uninitializated variables.

[ravi123]

Thank you so much for the response, it is actually only some part of my program, so the variables are not initialized here, that is why i declared them dynamically. and i will try to modify the changes you have told.thank you very much again!!