Find a first pseudopalindrome in the array - c

Question

I have a array of strings and I want to find the first pseudopalindrome in the array for every string (if there is any). So I decided to sort my array at first, then reverse the word and do a binary search for a reversed word. So here it is what I have so far:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char len(char *x){
char len = 0;
while (*x != '\0'){
x++;
len++;
}
return len;
}
char compare(char *x, char *y){
char x0 = &x;
char y0 = &y;
while (*x != '\0'){
if (tolower(*x) < tolower(*y)) return -1;
if (tolower(*x) > tolower(*y)) return 1;
x++;
y++;
}
// if we are here it means that strings are equal (case insensitive)
x = &x0;
y = &y0;
while (*x != '\0'){
if (*x > *y) return -1;
if (*x < *y) return 1;
x++;
y++;
}
// strings are equal (case sensitive)
return 0;
}
char *reverse(char *x){
int i, j;
char temp, *rev = NULL;
rev = malloc(sizeof(char)*(len(x)+1));
rev = strcpy(rev,x);
i = 0;
j = len(x) - 1;
while (i < j){
temp = rev[i];
rev[i] = x[j];
rev[j] = temp;
i++;
j--;
}
return rev;
}
int binsearch(char *x, char *A, int len){
int l, r, m, index;
l = 0;
r = len - 1;
index = -1;
while (l <= r){
m = (l + r) / 2;
if (compare(x, A[m]) == 0){
index = m;
r = m - 1;
}
else if (compare(x, A[m]) == -1) r = m - 1;
else l = m + 1;
}
return index;
}
int main()
{
int n, i, j, k, fnd;
char T[10000][101], temp[101];
scanf("%d", &n);
for (i = 0; i < n; i++){
scanf("%s", &T[i]);
}
for (i = 1; i < n; i++){
strcpy(temp, T[i]);
j = i - 1;
while (j >= 0 && compare(T[j], temp) == 1){
strcpy(T[j+1], T[j]);
j--;
}
strcpy(T[j+1], temp);
}
for (i = 0; i < n; i++){
fnd = binsearch(reverse(T[i]), T, n);
printf("%d", fnd);
}
return 0;
}
This program stops executing. The problem is probably with binary search as every function before executes well. But what's wrong with this binary search? Or what else can break the code?

Answer 1

Does the return type causing the problem .. for binary search no return type is mentioned
Edit 1. But you have not mentioned return type for function in its declaration
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
char len(char *x){
char len = 0;
while (*x != '\0'){
x++;
len++;
}
return len;
}
char compare(char *x, char *y){
char* x0 = x;
char* y0 = y;
while (*x != '\0'){
int a0 = tolower(*x);
int b0 = tolower(*y);
if ( a0 < b0)
return -1;
if ( a0 > b0)
return 1;
x++;
y++;
}
// if we are here it means that strings are equal (case insensitive)
x = x0;
y = y0;
while (*x != '\0'){
if (*x > *y) return -1;
if (*x < *y) return 1;
x++;
y++;
}
// strings are equal (case sensitive)
return 0;
}
char *reverse(char *x){
int i, j;
char temp, *rev = NULL;
rev = malloc(sizeof(char)*(len(x)+1));
rev = strcpy(rev,x);
i = 0;
j = len(x) - 1;
while (i < j){
temp = rev[i];
rev[i] = x[j];
rev[j] = temp;
i++;
j--;
}
return rev;
}
int binarysearch(char *x,char A[][101], int len){
int l, r, m, index;
l = 0;
r = len - 1;
index = -1;
while (l <= r){
m = (l + r) / 2;
if (compare(x, A[m]) == 0){
index = m;
r = m - 1;
}
else if (compare(x, A[m]) == -1) r = m - 1;
else l = m + 1;
}
return index;
}
int main()
{
int n, i, j, k, fnd;
char T[10000][101], temp[101];
scanf("%d", &n);
for (i = 0; i < n; i++){
scanf("%s", &T[i]);
}
for (i = 1; i < n; i++){
strcpy(temp, T[i]);
j = i - 1;
while (j >= 0 && compare(T[j], temp) == 1){
strcpy(T[j+1], T[j]);
j--;
}
strcpy(T[j+1], temp);
}
for (i = 0; i < n; i++){
fnd = binarysearch(reverse(T[i]), T, n);
printf("%d", fnd);
}
return 0;
}

Answer 2

Not really an answer, but code in comments is painful to read.
You may also try to simplify your code; it's quite astonishing to have some much code for just a palindrome; some functions you are reimplementing are part of standard c (strlen, strcasecmp, strdup)
The function for telling if a word is palindrome is expected to really simple; here a sample of what it could be
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
bool isspeudopalindrom(const char *x){
for (int i = 0; i < strlen(x) / 2; ++i) {
if (tolower(x[i]) != tolower(x[strlen(x) - 1 - i]))
return false;
}
return true;
}
int main(int argc, char *argv[])
{
for (int i = 1; i < argc; i++){
if (isspeudopalindrom(argv[i]))
printf("palindrom\n");
else
printf("not palindrom\n");
}
return 0;
}