My program aims to print each word in the sentence on a separate line.but I should print it with %s not %c! I already try to implement it but the program does not give me a correct output ! my idea is when you find null character
1- print the word
2- return the index of the temp array to 0 and store a new word
int main () {
char sen[100];
char cpy [100];
printf("Entter a sentence ");
gets(sen);
int len = strlen(sen);
int i = 0;
int k =0;
for (i=0 ; i<len;i++)
{
if (sen[i]!='\0')
{
cpy[k++]+=sen[i];
}
else{
printf("%s\n",cpy);
k=0;}
}
}
You confound null character and space character. Null character \0 stands for "end of string" : the strlen function returns the number of characters before the first \0.
In your forloop, you want to display each word separated by so you have to test with the caracter instead of \0.
Also to correctly display your string you have to end the string with the \0 character. So before the instruction printf you must do cpy[k] = '\0';.
if (sen[i]!='\0') will always be true as pointed by Julien Vernay, you need if (sen[i]!= ' ') instead of if (sen[i]!='\0'), as there are spaces between words, to seprate them.
Also in cpy[k++]+=sen[i]; you are adding sen[i] to cpy[k++] which seams weird, I think what you need is cpy[k++] = sen[i];
Modify your loop as follows...
for (i=0 ; i<len; i++) {
int flag = 0;
while(sen[i] == ' ') i++; // multiple spaces
while(sen[i] != ' ' && sen[i] != '\0') {
cpy[k++] = sen[i];
flag = 1;
i++;
}
if(flag) {
cpy[k] = '\0';
printf("%s\n",cpy);
k=0;
}
}
You can have to not bother with doing a copy - all you need to do is essentially replace spaces with new lines. So here is the code to do this:
#include <stdio.h>
int main()
{
char sen[100];
bool last_char_space = true;
printf("Please enter a sentence: ");
fflush(stdout);
fgets(sen, 100, stdin);;
for (int loop = 0; sen[loop]; ++loop) { // send[loop] is true until end of string - saves repeatedly calling strlen
if (send[loop] == ' ') { // A space
if (last_char_space) { // Last character not a space, put new line
fputc('\n', stdout);
}
last_char_space = true; // Record the fact that we are between words
} else {
fputc(sen[loop], stdout); // Not a space - print it
last_char_space = false; // We are working on a word
}
}
return 0;
}
Related
In C apparently strings are stored like an array with a null value or '\0' at the end. I wish to iterate over the string in a for loop and I need it to stop at '\0', not including it. I've tried many conditions for the if else and it all don't seem to work.
for example:
char patternInput[TEXTSIZE];
for(int i = 0; i<strlen(patternInput);i++)
{
if(patternInput[i]==NULL)
{
printf("\nlast character");
break;
}
else
{
printf("\n%c",patternInput[i]);
}
}
I've tried if(patternInput[i]==NULL), if(patternInput[i]==NUL),if(!patternInput[i]),if(patternInput[i]=='\0') and none of them seems to work.
If you're scanning the characters yourself, you can avoid the (redundant and somewhat expensive) strlen() call entirely, and instead use the value of patternInput[i] in the continuation-test of your for-loop:
char patternInput[TEXTSIZE] = "testing!";
for(int i = 0; patternInput[i] != '\0'; i++)
{
printf("\n%c",patternInput[i]);
}
printf("\nlast character\n");
Consider this code. This code prints 'Null character found' with position of the character. Notice the 'less than or equal to' in i<=strlen(str) in the loop invariant.
The last character at the length strlen + 1 is the '\0' character.
int i = 0;
char str[] = "Hello";
for(int i=0; i<=strlen(str); i++)
{
if(str[i]=='\0')
printf("Null character found at position %d", i);
}
I wrote a program to find the longest word in a string and print the number of letters in the longest word. But the code is not printing. I analyzed the program many times but I could not find the solution.
#include <stdio.h>
#include <string.h>
int main() {
char string[100] = "Hello Kurnool";
int i = 0, letters = 0, longest = 0;
start:
for (; string[i] !=' '; i++) {
letters++;
}
if (letters >= longest)
longest = letters;
if (string[i] == ' ') {
letters = 0;
i++;
goto start;
}
printf("%d", longest);
return 0;
}
Using goto is highly discouraged. You should convert your code to use a loop.
The main problem in your code is you do not stop the scan when you reach the end of the string.
Here is a modified version:
#include <stdio.h>
int main() {
char string[100] = "Hello Kurnool";
int i, letters, longest = 0, longest_pos = 0;
for (i = 0; string[i] != '\0'; i++) {
for (letters = 0; string[i] != '\0' && string[i] != ' '; i++) {
letters++;
}
if (letters > longest) {
longest = letters;
longest_pos = i - longest;
}
}
printf("longest word: %d letters, '%.*s'\n",
longest, longest, string + longest_pos);
return 0;
}
Note that the implementation can be simplified into a single loop:
#include <stdio.h>
int main() {
char string[100] = "Hello Kurnool";
int i, start = 0, longest = 0, longest_pos = 0;
for (i = 0; string[i] != '\0'; i++) {
if (string[i] == ' ') {
start = i + 1;
} else {
if (i - start > longest) {
longest = i - start;
longest_pos = start;
}
}
}
printf("longest word: %d letters, '%.*s'\n",
longest, longest, string + longest_pos);
return 0;
}
Below is my approach. You should use C's string manipulation functions. This is the correct way to deal with strings in C.
In the code below, first I acquire the required bytes to store the input string in heap. Then I use strtok to split the string into tokens based on a delemeter and get the length of each sub string. Finally I free the space that I have allocated with malloc.
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define phrase "Hello Kurnool"
int main()
{
char* string = malloc(strlen(phrase)+1);
strcpy(string,phrase);
int longest=0;
char *token;
char delimeter[2] = " ";
/* get the first token */
token = strtok(string, delimeter);
/* walk through other tokens */
while( token != NULL ) {
printf( " %s\n", token );
if(longest < strlen(token)){
longest = strlen(token);
}
token = strtok(NULL, delimeter);
}
printf("%d",longest);
free(string);
return 0;
}
People say - dont use goto but there is nothing inherently wrong with goto. Only thing is if goto is not used judiciously, it makes code more difficult to understand and maintain. For example, the way you have used it in your program ( instead of goto, a loop is perfect fit in such cases). Check this:
To use goto or not?
What is wrong with using goto?
Coming to your code, the for loop condition does not have check for terminating null character
for (; string[i] !=' '; i++) {
Hence it will not stop at the end of string.
To find the number of letters in longest word of string, you can do:
#include <stdio.h>
#include <string.h>
int main() {
char string[100] = "Hello Kurnool";
int i, letters = 0, longest = 0;
for (i = 0; string[i] != '\0'; i++) {
if (string[i] != ' ') {
letters++;
if (letters > longest) {
longest = letters;
}
} else {
letters = 0;
}
}
printf("longest : %d\n", longest);
return 0;
}
First of all,Please avoid using Goto, it is not a good practice.
Secondly, your loop will run infinite times when it iterates the second time because:
for(;string[i]!=' ';i++) // Here String[i] will never be equal to ' ' As there is no white space after your last word.
You can never expect what might be going wrong with your program if you are using
goto statement
which is never advisable to use rather it's bad programming if you use it. Secondly it looks like you are stuck in an infinite loop so her is a solution to your problem:
#include<stdio.h>
#include<string.h>
void main()
{
char s[1000];
scanf("%s",s);
int i=0;
int letters;
int longest=0;
while(s[i]!=NULL)
{
if(s[i]==' ')
{
if(longest>=letters)
{longest=letters;}
letters=0;
}
else
{letters++;}
}
printf("%d\n",longest);
}
So, what I have done is assuming a string s which is the input given by the user. You itterate through s till the last input given by the user after which it encounters a NULL character. Now you are searching for the length of the longest word, so you create a variable letters for counting the no. of letters in each word of the string. And if the string s encounters a space indicating the end of a word, then you check if the variable longest is greater than or less than the word count. And again you initialize letters to 0, so that it can start counting the next word from 0 again.So, by this method at the end i.e. after the while loop terminates we get our required output which is stored in the variable longest.
So, I guess this will print the no. of letters in the longest word.
I'm trying to create a program that checks if a given array/string is a palindrome or not and its not working. The program just prints "0" on every given array, even on palindromes.
int main()
{
char string[100]= {0};
char stringReverse[100]= {0};
int temp = 0;
int firstLetter = 0;
int lastLetter = 0;
printf("Please enter a word or a sentence: ");
fgets(string, 100, stdin);
strcpy(stringReverse , string); // This function copies the scanned array to a new array called "stringReverse"
firstLetter = 0;
lastLetter = strlen(string) - 1; //because in array, the last cell is NULL
// This while reverses the array and insert it to a new array called "stringReverse"
while(firstLetter < lastLetter)
{
temp = stringReverse[firstLetter];
stringReverse[firstLetter] = stringReverse[lastLetter];
stringReverse[lastLetter] = temp;
firstLetter++;
lastLetter--;
}
printf("%s %s", stringReverse, string);
if ( strcmp(stringReverse , string) == 0)
{
printf("1");
}
else
{
printf("0");
}
}
Lets say we implement a simple fun to do that
int check_palindrome (const char *s) {
int i,j;
for (i=0,j=strlen(s)-1 ; i<j ; ++i, --j) {
if (s[i] != s[j]) return 0; // Not palindrome
}
return 1; //Palindrome
}
I think this is far more simpler ;)
For the code posted in question:
Be aware of fgets(). It stops in the first '\n' or EOF and keeps the '\n' character.
So if you give radar for ex, the result string will be "radar\n", which doesn't match with "\nradar"
The Problem:
Let's say you enter the string RACECAR as input for your program and press enter, this puts a newline character or a '\n' in your buffer stream and this is also read as part of your string by fgets, and so your program effectively ends up checking if RACECAR\n is a palindrome, which it is not.
The Solution:
After you initialize lastLetter to strlen(string) - 1 check if the last character in your string (or the character at the lastLetter index is the newline character (\n) and if so, decrease lastLetter by one so that your program checks if the rest of your string (RACECAR) is a palindrome.
lastLetter = strlen(string) - 1; //because in array, the last cell is NULL
// Add these 2 lines to your code
// Checks if the last character of the string read by fgets is newline
if (string[lastLetter] == '\n')
lastLetter--;
fgets adds a '\n' at the end.
So if the user entered "aba", string contains "aba\n".
reverseString contains "\naba".
So it doesn't match.
After the fgets, add this code
int l = strlen(string) - 1;
string[l] = 0;
This will strip out the '\n' at the end before copying it to reverseString.
That aside, you can do this whole program inplace without the need of a second buffer or strcpy or strlen calls.
You have several issues in your code:
first you forgot the last closing brace };
then you forgot to remove the trailing \n (or maybe also \r under Windows) in string;
you don't need to revert the string into a new string; a one-pass check is enough:
Here is a working code:
#include <stdio.h>
#include <string.h>
int main()
{
char string[100]= {0};
int temp = 0;
int firstLetter = 0;
int lastLetter = 0;
printf("Please enter a word or a sentence: ");
fgets(string, 100, stdin);
firstLetter = 0;
lastLetter = strlen(string) - 1; //because in array, the last cell is NULL
while ((string[lastLetter]=='\n')||(string[lastLetter]=='\r')) {
lastLetter--;
}
// This while reverses the array and insert it to a new array called "stringReverse"
temp = 1;
while(firstLetter < lastLetter)
{
if (string[firstLetter] != string[lastLetter]) {
temp = 0;
break;
}
firstLetter++;
lastLetter--;
}
if ( temp )
{
printf("1");
}
else
{
printf("0");
}
}
You can do it by this simpleway also.
#include <stdio.h>
#include <string.h>
int main()
{
char string[10], revString[10];
printf("Enter string for reversing it...\n");
scanf("%s", string);
int stringLength = strlen(string);
for(int i = 0; string[i] != '\0'; i++, stringLength--)
{
revString[i] = string[stringLength - 1];
}
if(strcmp(string, revString) == 0)
printf("Given string is pelindrom\n");
else
printf("Given string is not pelindrom\n");
}
#include<stdio.h>
#include<string.h>`enter code here`
void fun(char *a);
int main ()
{
char p[100];
char *s=p;
printf("enter the string");
scanf("%[^\n]",s);
fun(s);
}
void fun(char *a)
{
if(*a && *a!='\n')
{
fun(a+1);
putchar(*a);
}
}
// use this approach better time complexity and easier work hope this helps
this is my first post in this forum so please be patient.
I need to make a short programm, where the user can enter 2 strings which should be attached afterwards.
I already got this code below (I am not allowed to use other "includes").
What I need to know is: How can I deny any spaces which the user will enter?
Example: 1. String "Hello " | 2. String "World" Result should be "HelloWorld" instead of "Hello World".
#include <stdio.h>
void main()
{
char eingabe1[100];
char eingabe2[100];
int i = 0;
int j = 0;
printf("Gib zwei Wörter ein, die aneinander angehängt werden sollen\n");
printf("1. Zeichenkette: ");
gets(eingabe1);
printf("\n");
printf("2. Zeichenkette: ");
gets(eingabe2);
printf("\n");
while (eingabe1[i] != '\0')
{
i++;
}
while (eingabe2[j] != '\0')
{
eingabe1[i++] = eingabe2[j++];
}
eingabe1[i] = '\0';
printf("Nach Verketten: ");
puts(eingabe1);
}
You have to filter out the spaces as you copy your strings.
You have two string indices, i for the first string and and j for the second string. You could make better use of these indices if you used i for the reading position (of both strings subsequently; you can "reuse" loop counters in independent loops) and j for the writing position.
Here's how. Note that the code attempts to prevent buffer overflow by only adding characters if there is space in the string. This check needs only to be done when copying the second string, because j <= i when you process the first string.
#include <stdio.h>
int main()
{
char str1[100] = "The quick brown fox jumps over ";
char str2[100] = "my big sphinx of quartz";
int i = 0;
int j = 0;
while (str1[i] != '\0') {
if (str1[i] != ' ') str1[j++] = str1[i];
i++;
}
i = 0;
while (str2[i] != '\0') {
if (str2[i] != ' ' && j + 1 < sizeof(str1)) str1[j++] = str2[i];
i++;
}
str1[j] = '\0';
printf("'%s'\n", str1);
return 0;
}
In addition to avoiding spaces between your two words, you also have to avoid the newline ('\n') character placed in the input buffer by the user pressing Enter. You can do that with a simple test after you have read the line with fgets() NOT gets(). gets() is no longer part of the standard C library and should not be used due to insecurity reasons. Plus fgets provides simple length control over the number of characters a user may enter at any time.
Below, you run into trouble when you read eingabe1. After the read, eingabe1 contains a '\n' character at its end. (as it would using any of the line-oriented input functions (e.g. getline(), fgets(), etc) To handle the newline, you can simply compare its length minus '1' after you loop over the string to find the nul character. e.g.:
if (eingabe1[i-1] == '\n') i--; /* remove trailing '\n', update i */
By simply reducing the index 'i', this will guarantee that the concatenation with eingabe2 will not have any spaces or newline characters between the words.
Putting the pieces together, and using fgets in place of the insecure gets, after #define MAX 100'ing a constant to prevent hardcoding your array indexes, you could come up with something similar to:
#include <stdio.h>
#define MAX 100
int main (void)
{
char eingabe1[MAX] = {0};
char eingabe2[MAX] = {0};
int i = 0;
int j = 0;
printf("Gib zwei Wörter ein, die aneinander angehängt werden sollen\n");
printf("1. Zeichenkette: ");
/* do NOT use gets - it is no longer part of the C library */
fgets(eingabe1, MAX, stdin);
putchar ('\n');
printf("2. Zeichenkette: ");
/* do NOT use gets - it is no longer part of the C library */
fgets(eingabe2, MAX, stdin);
putchar ('\n');
while (eingabe1[i]) i++; /* set i (index) to terminating nul */
if (i > 0) {
if (eingabe1[i-1] == '\n') i--; /* remove trailing '\n' */
while (i && eingabe1[i-1] == ' ') /* remove trailing ' ' */
i--;
}
while (eingabe2[j]) { /* concatenate string - no spaces */
eingabe1[i++] = eingabe2[j++];
}
eingabe1[i] = 0; /* nul-terminate eingabe1 */
printf("Nach Verketten: %s\n", eingabe1);
return 0;
}
Output
$ ./bin/strcatsimple
Gib zwei Wörter ein, die aneinander angehängt werden sollen
1. Zeichenkette: Lars
2. Zeichenkette: Kenitsche
Nach Verketten: LarsKenitsche
Let me know if you have any further questions. I have highlighted the changes with comments above.
/**
return: the new len of the string;
*/
int removeChar(char* string, char c) {
int i, j;
int len = strlen(string)+1; // +1 to include '\0'
for(i = 0, j = 0 ; i < len ; i++){
if( string[i] == c )
continue; // avoid incrementing j and copying c
string[ j ] = string[ i ]; // shift characters
j++;
}
return j-1; // do not count '\0';
}
int main(){
char str1[] = "sky is flat ";
char str2[100] = "earth is small ";
strcat( str2, str1 );
printf("with spaces:\n\t'%s'\n", str2) ;
removeChar(str2, ' ');
printf("without spaces:\n\t'%s'\n", str2 );
}
/**
BONUS: this will remove many characters at once, eg "\n \r\t"
return: the new len of the string;
*/
int removeChars(char* string, char *chars) {
int i, j;
int len = strlen(string);
for(i = 0, j = 0 ; i < len ; i++){
if( strchr(chars,string[i]) )
continue; // avoid incrementing j and copying c
string[ j ] = string[ i ]; // shift characters
j++;
}
string[ j ]=0;
return j;
}
Thank you everyone for all the answers.
I got the solution now.
I read some advices from you and will try to remember for the future.
See the code below:
(Excuse me for the strange names for the variables, I use german words)
A few notices:
I am not allowed to use library functions
I am not allowed to use fgets for some reasons as a trainee
#include <stdio.h>
void main()
{
char eingabe1[100];
char eingabe2[100];
int i = 0;
int j = 0;
printf("gib zwei wörter ein, die aneinander angehängt werden sollen\n");
printf("1. zeichenkette: ");
gets(eingabe1);
printf("\n");
printf("2. zeichenkette: ");
gets(eingabe2);
printf("\n");
//Attach Strings
while (eingabe1[i] != '\0')
{
i++;
}
while (eingabe2[j] != '\0')
{
eingabe1[i++] = eingabe2[j++];
}
//Remove Space
eingabe1[i] = '\0';
i = 0;
j = 0;
while (eingabe1[i] != '\0')
{
if (eingabe1[i] != 32)
{
eingabe2[j++] = eingabe1[i];
}
i++;
}
eingabe2[j] = '\0';
printf("Nach verketten: ");
puts(eingabe2);
}
Sounds like homework to me.
I just wanted to mention that you probably shouldn't use sizeof() on strings these days because there may be multibyte characters in there. Use strlen() instead. The only time sizeof() would be appropriate is if you're going to malloc() a certain number of bytes to store it.
I write little loops fairly often to do low level text stuff one character at a time, just be aware that strings in C usually have a 0 byte at the end. You have to expect to encounter one and be sure you put one on the output. Space is 0x20 or decimal 32 or ' ', it's just another character.
I'm writing a function called GetPattern() that will be used in my main() function.
Here's the context of how my main() uses the GetPattern() function.
int main(void)
{
int attempt=0, option=-1;
char pattern[SIZE+1], replacement[SIZE+1];
char name[20];
FILE *in, *out;
printf("Enter the pattern to find:");
GetPattern(pattern);
out = CreateFile();
Find(in, pattern, out);
fclose(in);
fclose(out);
return 0;
}
And here's my GetPattern() function:
void GetPattern(char *tmp)
{
// prompt the user for the pattern to be found/replaced
// note: any character, including ' ', maybe be part of the pattern
// we assume that the pattern has no more than 20 characters. If the user
// enters more than 20 characters, only the first 20 will be used.
int i;
for (i = 0; i < 20; i++) // iterate 20 times
{
scanf(" %c", &tmp[i]);
if (tmp[i] == '\n') // if user hits enter, break the loop
{
tmp[i] = '\0'; // insert '\0' at the end of the array
break;
}
else
tmp[i+1] = '\0'; // insert '\0' at the end of the array
}
printf("%s\n", tmp); // see what's in tmp[]
return;
}
The GetPattern() function works by itself; separate from the main() function, but when I put it into main, it exclusively accepts 20 characters and no less. Even when I hit ENTER (i.e., '\n'), the loop doesn't break--it keeps going.
Do you see anything obviously wrong with this code?
I think using getc() will help you.
for (i = 0; i < 20; i++) // iterate 20 times
{
//scanf(" %c", &tmp[i]);
tmp[i]=getc(stdin);/////
if (tmp[i] == '\n') // if user hits enter, break the loop
{
tmp[i] = '\0'; // insert '\0' at the end of the array
break;
}
else
tmp[i+1] = '\0'; // insert '\0' at the end of the array
}