I'm trying to determine if a phrase is a palindrome (a word that is the same from left to rigth) or not but i can't make it work. What's wrong?, i can't use pointers or recursion or string type variables
#include <stdio.h>
#include <string.h>
int main()
{
int i,j = 0,length;
char space = ' ';
char phrase [80],phrase2[80],phrase3[80];
printf("Give me the phrase: ");
gets(phrase);
length = strlen(phrase);
for(i =0; i <= length - 1; i++)
{
if(phrase[i] != space) //Makes the phrase without spaces
{
phrase2[i] = phrase[i];
j++;
}
}
for(i = length -1; i >= 0;i--)
{
if(phrase[i] != space) //Makes the phrase backwards an without spaces
{
phrase3[j] = phrase[i];
j++;
}
}
length = strlen(phrase2);
for(i =0; i <= length -1;i++) //Compare the phrases to know if they are the same
{
if(phrase2[i] != phrase3[i])
{
printf("It's not a palindrome\n");
return 0;
}
}
printf("It's a palindrome\n");
return 0;
}
Try this:
for(i =0, j=0; i <= length - 1; i++)
{
if(phrase[i] != space) //Makes the phrase without spaces
{
phrase2[j] = phrase[i];
j++;
}
}
for(i = length -1, j = 0; i >= 0;i--)
{
if(phrase[i] != space) //Makes the phrase backwards an without spaces
{
phrase3[j] = phrase[i];
j++;
}
}
length = j;
Update
In response to Praetorian's post here's the code to do it without copying the string.
#include <stdio.h>
#include <string.h>
int main()
{
int i, j, length;
char space = ' ';
char phrase[80];
printf("Give me the phrase: ");
gets(phrase);
length = strlen(phrase);
for( i = 0, j = length - 1; i < j; i++, j-- ) {
while (phrase[i] == space) i++;
while (phrase[j] == space) j--;
if( phrase[i] != phrase[j] ) {
printf("It's not a palindrome\n");
return 0;
}
}
printf("It's a palindrome\n");
return 0;
}