How do i create a "matrix" with words in C - arrays

Question

The problem is the following:
Have to check if the words in the matrix are palindromes or not. Have to read the words as well.
My main problem is introducing the words because until now I could only do a function reading the first letter, not the whole word.
After that, I think that I can check alone if it is a palindrome or not.
This is an example of data:
mat←["ac" "lup" ]
["ou" "lupul"]
["ABBA" "greu" ]
m←3 number of rows
n←2 number of columns
This what I wrote until now:
A function where you introduce the words:
char** read(int *m ,int *n)
{
printf("No of lines=");
scanf("%d",m);
printf("No of columns=");
scanf("%d",n);
char **a=(char**)malloc(*m*sizeof(char*));
for (int i=0;i<*m;i++)
{
a[i]=(char*)malloc(*n*sizeof(char));
for (int j=0; j<*n; j++)
{
fflush(stdin);
printf("Element [%d][%d]=",i,j);
gets(a[i]+j); // <=> &a[i][j]
}
}
return a;
}
Another one which displays it:
void display(char **x, int m, int n)
{
for (int i=0; i<m; i++)
{
for (int j=0; j<n; j++)
printf("%c ",x[i][j]);
printf("\n");
}
}
Another one which deletes the data:
void freematrix(char **x, int m)
{
for (int i=0; i<m; i++)
free(x[i]);
free(x);
}
This is the main part:
int main()
{
int m, n;
char **mat;
mat=read(&m,&n);
display(mat,m,n);
freematrix(mat,m);
return 0;
}

Answer 1

Try this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_ROWS 8 // to limit the usecase
#define MAX_COLS 8
#define MAX_MAT_STR_LEN 15 //
char* str_dupe (const char* str, const int max_slen)
{
if (!str || max_slen < 1) return NULL;
char* dupe = malloc (max_slen + 1);
if (!dupe) {
perror("\nERROR: str_dupe-malloc");
return NULL;
}
dupe[max_slen] = '\0'; // guard
for (int ci =0; ci < max_slen; ++ci) {
dupe[ci] = str[ci];
if ('\0' == dupe[ci])
break; // stop copying
}
return dupe;
}
void free_strMatrix (char ***sm, const int rows, const int cols)
{
if (!sm || rows < 1 || cols < 1) return;
for (int ri = 0; ri < rows; ++ri) {
if (sm[ri]) {
for (int ci = 0; ci < cols; ++ci) {
if (sm[ri][ci]) { // check if it's NULL
free (sm[ri][ci]);
sm[ri][ci] = NULL; //prevent dangling pointers
}
}
free (sm[ri]); // row of string pointers
sm[ri] = NULL; // good practice
}
}
free (sm);
}
char*** read_strMatrix (int *rows, int *cols)
{
while (1) {
printf ("\nChoose Rows [1..%d]: ", MAX_ROWS);
if (1 == scanf("%d", rows) && *rows > 0 && *rows <= MAX_ROWS)
break;
else
printf ("\nERROR: Invalid Row-Count. Try Again!");
}
while (1) {
printf ("\nChoose Columns [1..%d]: ", MAX_COLS);
if (1 == scanf("%d", cols) && *cols > 0 && *cols <= MAX_COLS)
break;
else
printf ("\nERROR: Invalid Column-Count. Try Again!");
}
char*** sm = (char***) calloc ((*rows), sizeof (char**));
if (NULL == sm) {
perror("read_strMatrix-malloc-1");
return NULL;
}
for (int ri = 0; ri < *rows; ++ri) {
sm[ri] = (char**) calloc ((*cols), sizeof (char*));
if (NULL == sm[ri]) {
perror ("read_strMatrix-malloc-2");
//ideally you should free allocated memory before return
free_strMatrix(sm, *rows, *cols);
return NULL;
}
}
char str[256]; //interim string buffer;
for (int ri = 0; ri < *rows; ++ri) {
for (int ci=0; ci < *cols; ++ci ) {
printf ("String for strMatrix[%d][%d] : ", ri, ci);
// strings more than 255 chars will be split ; so be within limit duing input
while (1 != scanf ("%255s", str));
// only copying MAX_MAT_STR_LEN chars
sm[ri][ci] = str_dupe (str, MAX_MAT_STR_LEN);
if (NULL == sm[ri][ci]) {
perror("read_strMatrix-strndup");
//ideally you should free allocated memory before return
free_strMatrix (sm, *rows, *cols);
return NULL;
}
}
printf ("\n");
}
return sm;
}
void disp_strMatrix (char ***sm, const int rows, const int cols)
{
if (!sm || rows < 1 || cols < 1) return;
printf ("\nStringMatrix [%d][%d]:\n", rows, cols);
for (int ri = 0; ri < rows; ++ri) {
if (sm[ri]) {
for (int ci = 0; ci < cols; ++ci)
printf ("%s\t", sm[ri][ci]);
}
printf ("\n");
}
printf ("\n");
}
int main()
{
int rows, cols;
char ***strMatrix;
strMatrix = read_strMatrix (&rows, &cols);
if (!strMatrix) {
printf ("\nERROR: reading strMatrix\n");
return 1;
}
disp_strMatrix (strMatrix, rows, cols);
free_strMatrix (strMatrix, rows, cols);
strMatrix = NULL; // good practice
return 0;
}
You can also prepare an input.txt file like:
3 4
aaaaa sssss ffg gggg
hhhh jj kkkkkk lllll
qqq wwwww eeeee rrrrr
On Linux you can run the program like:
./a.out < input.txt