So I have been trying to make sure that I can check whether an user-inputted word is a palindrome or not by using function prototypes. However, I am getting an error in the end saying "Segment Fault: 11". I am fairly new to using function prototypes so if anyone can help me with solving anything that can be going on in the body of the function definition, then please point it out to me.
#include <stdio.h>
void palindrome_check(int ch_length, char text)
int main(void)
{
int length;
printf("Enter how many characters are in the message: ");
scanf("%d", &length);
char m;
printf("Enter the message: ");
scanf("%c", &text);
palindrome_check(l, m);
return 0;
}
void palindrome_check(int ch_length, char text)
{
char msg[ch_length];
text = msg[ch_length];
int count = 0;
while (count < ch_length)
{
count++;
scanf("%c", &msg[count]);
}
int i, j;
for (i = 0; i < ch_length; i++)
{
msg[j] = msg[ch_length - i];
}
if (text[i] == text[j])
{
printf("The message you entered is a palindrome!\n");
}
else
{
printf("It's not a palindrome.\n");
}
}
I couldn't understand some of your code it seemed you were doing some unnecessary things. What was msg for? This should work if I understood your problem correctly:
#include <stdio.h>
#include <string.h>
void palindrome_check(int ch_length, char text []);
int main(void)
{
char text [100];
/*
int length;
printf("Enter how many characters are in the message: ");
scanf("%d", &length);
Not necessary if you use strlen()*/
printf("Enter the message: ");
fgets(text,100,stdin); /*Using fgets() to allow spaces input*/
/*Strip the newline*/
text [strlen(text)-1]='\0';
palindrome_check(strlen(text),text);
return 0;
}
void palindrome_check(int ch_length, char text [])
{
int i;
for (i = 0; i < ch_length; i++)
{
if(text [i] != text [ch_length-i-1])
{
printf("It's not a palindrome.\n");
return;
}
}
printf("It is a palindrome!\n");
}
Related
Starting to learn C. The main function is executing fine, but the program finishes running without ever executing the second function. I feel like I'm making a mistake here in the for loop in main.
int check_key_length(int count);
int main(void)
{
char key[20];
int count = 0;
printf("Enter key: ");
scanf("%s", key);
for(int i = 0; i < strlen(key); i++)
{
if (key[i] != ' ')
count++;
}
printf("Total number of characters in a string: %d", count);
}
int check_key_length(int count)
{
int set_amount = 26;
if (count < set_amount)
printf("Error: Your key is too short! Please input 26 chars\n");
else if (count > set_amount)
printf("Error: Your key is too long! Please input 26 chars\n");
else
string message = get_string("Enter string to encrypt: ");
return 0;
}
You forward declared your function, provided a definition for it, but you need to call the function in your main for your machine to execute it, something like this calls your function as expected
#include <stdio.h>
#include <string.h>
int check_key_length(int count);
int main(void)
{
char key[27];
int count = 0;
int strLength;
do {
printf("Enter key: ");
scanf("%s", key);
strLength = strlen(key);
} while(check_key_length(strLength) != 0);
for(int i = 0; i < strLength; i++)
{
if (key[i] != ' ')
{
count++;
}
}
printf("Total number of characters in a string: %d\n", count);
return 0;
}
int check_key_length(int count)
{
int set_amount = 26;
if (count < set_amount)
{
printf("Error: Your key is too short! Please input 26 chars\n");
return -1;
}
else if (count > set_amount)
{
printf("Error: Your key is too long! Please input 26 chars\n");
return -2;
}
else
{
return 0;
}
}
Note I had to modify the code a bit for it to build without any warning or error, I probably changed the behavior in a way you're not expecting so check my code before pasting it in
I am trying to display and print a word from the user and store it into my array which is called
char word[20]
But I am having trouble. I know we use a "for loop" to scan it into the array but I keep going in circles and I believe the problem is with the i < 20.
I researched this and found that the answers to this are extremely experienced and I need a really basic way of doing it without the extra stuff. So all I want is to get word from the user, store it and print it onto the screen.
Can someone help without experienced code?
Code in C
char getWord(char word[]);
int main()
{
char word[20];
getWord(word);
return 0;
}
char getWord(char word[])
{
int i;
printf("Enter a word: ");
for (i = 0; i < 20; i++)
{
scanf(" %c", &word[i]);
}
return word;
}
All you want is
#include <stdio.h>
int main() {
char word[20];
scanf("%s", word); // Read and store
printf("%s\n", word); // Print
return 0;
}
You can use fgets and puts to read and write a string.
#include<stdio.h>
#define MAX 20
int main()
{
int ar[MAX], i, count;
fgets(ar, MAX, stdin); //it will accept whitespaces as well
puts(ar); //displaying entered string
return;
}
if you want to read via characters, ending character should be set to null character for it to be string.
char getWord(char word[]);
int main()
{
char word[20]
getWord(word);
printf("%s\n", word);
return 0;
}
char getWord(char word[])
{
int i;
char c;
printf("Enter a word: ");
for (i = 0; i < 19; i++)
{
scanf("%c", &c);
if ( c == '\n' )
break;
word[i]=c;
}
word[i]='\0';
return word;
}
This is what I theorized it should be but it seemed like it doesn't work.
HELP PLEAZEE
int main()
{
char input[50];
int i;
do{
printf("ENTER A CHARACTER:");
scanf("%s",&input);
if(isalpha(input)!=0){
printf("YOU INPUTTED A CHARACTER");
i++;
}else{
printf("INVALID INPUT\n");
}
}while(i!=1);
}
isalpha takes an integer as an argument.
You are giving a char array.
You should loop for the number of characters given in input[], if you want more than one character (hard to tell from this code).
This exits if you give exactly one character but keeps going if you give more than one:
#include <stdio.h>
#include <string.h>
int main()
{
char input[50];
int i = 0, j;
size_t len = 0;
do
{
printf("ENTER A CHARACTER:");
scanf("%s",&input);
len = strlen(input);
for(j = 0; j < len; j++) {
if(isalpha(input[j]))
{
i++;
printf("YOU INPUTTED A CHARACTER %d\n", i);
}
else
{
printf("INVALID INPUT\n");
break;
}
}
} while(i!=1);
}
I am programming a palindrome code to check whether a given string is a palindrome or not. Eg: mom, 1001 ...
MY_CODE:
#include <stdio.h>
#include <stdlib.h>
#include <stdio_ext.h>
int main()
{
int i,n;
char p[999];
char flag;
printf("number of characters in the strings");
scanf("%d",&n);
printf("Enter string: ");
for (i=0;i<n;i++)
{
printf("\n");
__fpurge(stdin);
scanf("%c",&p[i]);
}
for (i=0;i<n;i++)
{
if (p[i]==p[n-1-i])
{
flag=0;
break;
}
else flag=1;
}
if (flag==1)
printf("It's not a palindrome");
if (flag==0)
printf("It's a palindrome.");
return 0;
}
I am trying to do that with the idea that if the last and first characters are matched and so on for the next characters. If they are all matched the string is a palindrome otherwise it is not,as simple as that but my output
shows 123;mom; and every nonsense, a palindrome ("even the word 'nonsense' :D).
Can someone guide me?
P.S.: I am a newbie and learning C. My OS: Ubuntu 15.10.
You are checking if characters are the same and is so, setting flag=0, to say it is a palindrome, but that will happen for the 1st match - if other matches do not occur, the flag is never set to not be a palindrome.
The better way is assume it is a palindrome and then if anything provides otherwise, set it as false.
#include <stdio.h>
#include <string.h>
int main()
{
char p[999];
printf("Enter string: ");
if(fgets(p, sizeof(p), stdin))
{
int palindrome = 1;
int i;
int n;
n = strlen(p);
/* handle new line at end of fgets input */
if(p[n-1] == '\n')
p[n-1] = '\0';
n = strlen(p);
/* 0 length string (after newline removed) - not a palindrome */
if(n == 0) palindrome = 0;
for(i=0;i<n/2;i++)
{
/* look for a chatacter pair that doesn't match - if find, then we don't have a palindrome */
if(p[i] != p[n-1-i])
palindrome = 0;
}
if(palindrome)
printf("is a palindrome\n");
else
printf("is not a palindrome\n");
}
return 0;
}
From your code, I have a couple of things to say as follows.
#include <string.h>
#include <stdio.h>
// #include <stdlib.h> // this is not necessary.
int main()
{
// int i,n;
// char p[999];
// char flag;
// ######################################################
// You literally don't need to input the number of characters since you can get the string's length from `strlen`.
// In addition, different inputs yield different lengths,
// therefore, it is not applicable if the input becomes extremely long, for example.
//
// printf("number of characters in the strings");
// scanf("%d",&n);
// printf("Enter string: ");
// for (i=0;i<n;i++)
// {
// printf("\n");
// __fpurge(stdin);
// scanf("%c",&p[i]);
// }
// ######################################################
char str[100];
printf( "Enter a value :");
gets( str );
int i=0;
int n;
n = strlen(str)-1;
while (i<n)
{
if (str[i++] != str[n--])
{
printf("%s is Not palidrome\n", str);
return 0;
}
}
printf("%s is palidrome\n", str);
// for (i=0;i<n;i++)
// {
// if (p[i]==p[n-1-i])
// {
// flag=0;
// break;
// }
// else flag=1;
// }
// if (flag==1)
// printf("It's not a palindrome");
// if (flag==0)
// printf("It's a palindrome.");
return 0;
}
With a slightly modification as above, that code works well.
Note: The palindrome problem is a classical problem, and you literally can find many solutions from the internet. You can refer the solution code in C at here.
Update: Here is my update with fgets and while-loop.
#include <string.h>
#include <stdio.h>
int main()
{
char str[100];
printf( "Enter a string (char/value) :");
fgets (str, 100, stdin);
int i=0;
int n;
n = strlen(str)-1;
while (i<n)
{
if (str[i++] != str[n--])
{
printf("%s is Not palidrome\n", str);
return 0;
}
}
printf("%s is palidrome\n", str);
return 0;
}
My program in C which is Palindrome has an error in its function. My function is not comparing the 2 characters in my string. When I type a single character it answers palindrome but if it is two or more always not palindrome.
Code:
int IntStrlength=strlen(StrWord);
int IntCtr2=0;
int IntCtr=1, IntAnswer;
while(IntCtr<=(IntStrlength/2)){
printf(" %d %d\n", IntCtr2,IntStrlength);
if(StrWord[IntStrlength] != StrWord[IntCtr2]){
IntAnswer=0;
printf(" %d=Not Palindrome", IntAnswer);
exit (0);
}//if(StrWord[IntCtr2]!=StrWord[IntStrlength]) <---------
else{
IntCtr2++;
IntStrlength--;
}// else <--------
IntCtr++;
}//while(IntCtr<IntStrlength/2) <-----------
IntAnswer=1;
printf(" %d=Palindrome", IntAnswer);
return ;
}
Single character:
Two or more characters:
Why not write it like this
int wordLength = strlen(StrWord);
for (int i=0;i<(wordLength/2);i++) {
if (StrWord[i] != StrWord[wordLength-i-1]) {
return 0;
}
}
return 1;
For words with an even length (say 8) the counter will go from 0 to 3, accessing all letters. For uneven words (say 7) the c ounter will go from 0 to 2, leaving the middle element unchecked. This is not necessary since its a palindrome and it always matches itself
#include<stdio.h>
int check_palindrom(char *);
int main()
{
char s1[20];
printf("Enter the string...\n");
gets(s1);
int x;
x=check_palindrom(s1);
x?printf("Palindrom\n"):printf("Not Palindrom\n");
}
int check_palindrom(char *s)
{
int i,j;
for(i=0;s[i];i++);
for(i=i-1,j=0;i>j;i--,j++)
if(s[i]!=s[j])
return 0;
if(s[i]==s[j])
return 1;
}
Enter the string...
radar
Palindrom
I've seen this algorithm before in a interview book called "Cracking the Coding Interview".
In it the author shows a very simple and easy implementation of the code. The code is below: Also here is a video explaining the code.
#include<stdio.h>
#include<string.h> // strlen()
void isPalindrome(char str[]);
int main(){
isPalindrome("MOM");
isPalindrome("M");
return 0;
}
void isPalindrome(char str[]){
int lm = 0;//left most index
int rm = strlen(str) - 1;//right most index
while(rm > lm){
if(str[lm++] != str[rm--]){
printf("No, %s is NOT a palindrome \n", str);
return;
}
}
printf("Yes, %s is a palindrome because the word reversed is the same \n", str);
}
You can do this like this:
#include <stdio.h>
#include <string.h>
int check_palindrome(char string []);
int main()
{
char string[20];
printf("Enter the string...\n");
scanf ("%s", &string);
int check;
check = check_palindrome (string);
if (check == 0)
printf ("Not Palindrome\n");
else
printf ("Palindrome\n");
return 0;
}
int check_palindrome (char string [])
{
char duplicate [];
strcpy (string, duplicate);
strrev (string);
if (strcmp (string, duplicate) == 0)
return 1;
else
return 0;
}
This uses the strcmp and strrev function.
Take a look at this code, that's how I have implemented it (remember to #include <stdbool.h> or it will not work):
for(i = 0; i < string_length; i++)
{
if(sentence[i] == sentence[string_lenght-1-i])
palindrome = true;
else
{
palindrome = false;
break;
}
}
Doing that it will check if your sentence is palindrome and, at the first occurence this is not true it will break the for loop. You can use something like
if(palindrome)
printf(..);
else
printf(..);
for a simple prompt for the user.
Example :
radar is palindrome
abba is palindrome
abcabc is not palindrome
Please , pay attention to the fact that
Abba
is not recognized as a palindrome due to the fact that ' A ' and 'a' have different ASCII codes :
'A' has the value of 65
'a' has the value of 97
according to the ASCII table. You can find out more here.
You can avoid this issue trasforming all the characters of the string to lower case characters.
You can do this including the <ctype.h> library and calling the function int tolower(int c); like that :
for ( ; *p; ++p) *p = tolower(*p);
or
for(int i = 0; str[i]; i++){
str[i] = tolower(str[i]);
}
Code by Earlz, take a look at this Q&A to look deeper into that.
EDIT : I made a simple program to do this, see if it can help you
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include <ctype.h>
void LowerCharacters(char *word, int word_lenth);
int main(void){
char *word = (char *) malloc(10);
bool palindrome = false;
if(word == 0)
{
printf("\nERROR : Out of memory.\n\n");
return 1;
}
printf("\nEnter a word to check if it is palindrome or not : ");
scanf("%s", word);
int word_length = strlen(word);
LowerCharacters(word,word_length);
for(int i = 0; i < word_length; i++)
{
if(word[i] == word[word_length-1-i])
palindrome = true;
else
{
palindrome = false;
break;
}
}
palindrome ? printf("\nThe word %s is palindrome.\n\n", word) : printf("\nThe word %s is not palindrome.\n\n", word);
free(word);
return 0;
}
void LowerCharacters(char *word, int word_length){
for(int i = 0; i < word_length; i++)
word[i] = tolower(word[i]);
}
Input :
Enter a word to check if it is palindrome or not : RadaR
Output :
The word radar is palindrome.
This code may help you to understand the concept:
#include<stdio.h>
int main()
{
char str[50];
int i,j,flag=1;
printf("Enter the string");
gets(str);
for(i=0;str[i]!='\0';i++);
for(i=i-1,j=0;j<i;j++,i--)
{
str[i]=str[i]+str[j];
str[j]=str[i]-str[j];
str[i]=str[i]-str[j];
}
for(i=0;str[i]!='\0';i++);
for(i=i-1,j=0;j<i;j++,i--)
{
if(str[i]==str[j]){
flag=0;
break;
}
}if(flag==0)
{
printf("Palindrome");
}else
{
printf("Not Palindrome");
}
}
I have solution for this
char a[]="abbba";
int i,j,b=strlen(a),flag=0;
for(i=0,j=0; i<b; i++,j++)
{
if(a[i]!=a[b-j-1])
{
flag=1;
break;
}
}
if(flag)
{
printf("the string is not palindrum");
}
else
{
printf("the string is palindrum");
}
This may works for you
#include <stdio.h>
#include <stdlib.h>
int main(void) {
setbuf(stdout,NULL);
int i,limit;
char string1[10];
int flag=0;
printf("enter a string");
scanf("%s",string1);
limit=strlen(string1);
for(i=0;i<limit;i++){
if(string1[i]!=string1[limit-i-1]){
flag=1;
break;
}
} if(flag==1){
printf("entered string is not palindrome");
}else{
printf("entered string is palindrome");
}
return EXIT_SUCCESS;
}