Thread: Can't string compare

Our aim is to create a palindrome program.for example input Never odd or even and output This is a palindrome.This is what i have done so far but i am stuck in string compare m=strcmp(a[0],a[1]);.Thanks in advance.

Code:

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



char * remSpaces(char *ch){
char *ch2 = ch;
int i,j=0;
for(i=0;i<=strlen(ch);i++){
if(ch[i]!=' '){
ch2[j] = ch[i];
j++;
}
}

return ch2;

}




int main()
{
    int m;
    int i;
    char*a;
    char *ch = malloc(256);

    gets(ch);



    a=remSpaces(ch);
    printf("%s",a);
    m=strcmp(a[0],a[1]);





return 0;
}

a[0] and a[1], in your main() function are chars, not strings.
You cannot call strcmp() with chars.
Either make a[0] and a[1] strings (this is wrong for your problem) or use another comparison method (comparing the chars themselves).

Originally Posted by qny

a[0] and a[1], in your main() function are chars, not strings.
You cannot call strcmp() with chars.
Either make a[0] and a[1] strings (this is wrong for your problem) or use another comparison method (comparing the chars themselves).

So why this doesnt work?

Code:

int main()
{
    int m=0;
    int i;

    char *ch = malloc(256);

    gets(ch);



    char*a=remSpaces(ch);
    printf("%s",a);
     for (i=0;i<=strlen(a);i++){
      if (a[i]!=a[i-strlen(a)]){
       printf("5");

      }


    }





return 0;
}

a[i-strlen(a)]

first time through the loop, i=strlen(a) is a negative number.
also, "Never odd or even" is not a palindrome because 'N' != 'n'.

they told us to use toupper()..

Καλησπερα συντεκνε, αν και δεν ειμαι κρητικος!

toupper just converts the letter to an uppercase letter.

Notice that gets is quite different from fgets: not only gets uses stdin as source, but it does not include the ending newline character in the resulting string and does not allow to specify a maximum size for str (which can lead to buffer overflows). So use fgets instead

Also notice that m is an unused variable.

When i want to compare a string i do this

Code:

#include <stdio.h>

int main(void)
{
     char* str1 = "Greece";
    char* str2 = "Crete";

    char c1 = 'a';
    char c2 = 'b';

    if(strcmp(str1,str2)==0) {
        printf("Strings are the same!!\n");
    }
    else {
        printf("Strings are NOT the same!!\n");
    }

    if(c1 == c2) {
         printf("c1 and c2 are the same!!\n");
    }
    else {
         printf("c1 and c2 are NOT the same!!\n");
    }

    /* Because str1 and str2 are pointers to char, we can handle them as  */
    /* arrays as well.Do not make the mistake to consider that pointers   */
    /* are the same as arrays.They have some common properties, but there */
    /* are not equivalent                                                 */
    if(str1[2] == str2[2]) {
         printf("Third letter of Greece and Crete are the same!\n");
    }
    else {
         printf("We did something wrong!\n");
    }
    return 0;
}

Hope this helps