Check Palindrome in C

#include <stdio.h>
#include <string.h>
void main()
{
char string[20];
int i, j, length=0, flag=0;

printf("\nEnter The desired String string: ");
gets(string);
for (i=0; string[i]!='\0'; i++)
{
length++;
i = 0;
j = length-1;
while (i < length)
{
if (string[i] != string[j])
{
flag = 1;
break;
}
i++;
j--;
}
if (flag == 0)
{
printf("\n Your Desired String is palindrome");
}
else
{
printf("\nYour Desired String is not palindrome");
}
getch();

}