I'm trying to make a program in C that reads a word and prints if there are any duplicates and if so the number of occurrences. It works (as you can see in the attached pic) but once a letter has been printed I don't want it to reprint the same letter.
I've tried storing the duplicate chars in an array and then comparing the new duplicate to the duplicate array but it doesn't seem to be working.
Anyone know a simple way to not reprint?
#include <stdio.h>
#include <string.h>
int main(void) {
char word[100];
int x, i, j, freq, duplicates;
printf("Enter a word>\n");
scanf("%s", word);
x = strlen(word);
duplicates = 0;
freq = 1;
for(; i < x; i++) {
j = 0;
for(; j < x; j++) {
if ((word[i] == word[j]) && (i != j)) {
freq = freq + 1;
}
}
if (freq >= 2) {
printf("Duplicate letter: %c, Occurences: %d\n", word[i], freq);
duplicates = 1;
freq = 1;
}
}
if (duplicates < 1) {
printf("No duplicates found\n");
}
return 0;
}
Your problem here is in fors that look for the duplicate letter
The first one should go throw the string to look for all letters:
for (i = 0; i < x; i++) {
The second should look for the occurrence of the same character:
for (j = i; j < x; j++) {
Its because it runs once on each time it finds t and e respectively. One solution would be to find all occurrences of that char in the char array after printing the duplicate notification and removing it.
char * removeLetterFromArray(int toBeRemoved, char* string, int stringLength){
char * newString = malloc(stringLength * sizeof(char));
for(int i = 0; i < toBeRemoved; i++){
newString[i] = string[i];
}
for(int i = toBeRemoved; i < stringLength; i++){
newString[i] = string[i + 1];
}
return newString;
}
that code should remove the letter that you define the index of with toBeRemoved
So after you find a letter that has a duplicate loop through the code to find all places that letter occurs and pass them indexs to the above method.
If you do not wish to use the above method another option would be to create an array of letters that have already been output and ignore these letters in the future.
Related
The problem: After the convert_tolower(words) function is completed I want to add a new word in the words array( if the words array has less than 5 words)..But I am getting either errors or unexpected results(e.g some weird characters being printed)...What i thought is shifting the elements of the words array and then work with pointers because I am dealing with strings.But I am having quite some trouble achieving that..Probably the problem is in lines
35-37
How I want the program to behave:
Get 5 words(strings) at most from user input
Take these strings and place them in an array words
Convert the elements of the array to lowercase letters
After the above,ask the user again to enter a new word and pick the position of that word.If the words array already has 5 words then the new word is not added.Else,the new word is added in the position the user chose.(The other words are not deleted,they are just 'shifted').
Also by words[1] I refer to the first word of the words array in its entirety
The code:
#include <stdio.h>
#include <string.h>
#define W 5
#define N 10
void convert_tolower(char matrix[W][N]);
int main() {
int j = 0;
int i = 0;
int len = 0;
char words[W][N] = {{}};
char test[W][N];
char endword[N] = "end";
char newword[N];
int position;
while (scanf("%9s", test), strcmp(test, endword)) {
strcpy(words[i++], test);
j++;
len++;
if (j == W) {
break;
}
}
convert_tolower(words);
printf("Add a new word\n");
scanf("%9s", newword);
printf("\nPick the position\n");
scanf("%d",position);
if (len < W) {
for (i = 0; i < W-1; i++) {
strcpy(words[i], words[i + 1]); /*Shift the words */
words[position] = newword;
}
}
for (i = 0; i < W; i++) {
printf("%s", words[i]);
printf("\n");
}
printf("End of program");
return 0;
}
void convert_tolower(char matrix[W][N]) {
int i;
int j;
for (i = 0; i < W; i++) {
for (j = 0; j < N; j++) {
matrix[i][j] = tolower(matrix[i][j]);
}
}
}
This initialization
char words[W][N] = {{}};
is incorrect in C. If you want to zero initialize the array then just write for example
char words[W][N] = { 0 };
In the condition of the while loop
while (scanf("%9s", test), strcmp(test, endword)) {
there is used the comma operator. Moreover you are using incorrectly the two-dimensional array test instead of a one-dimensional array
It seems you mean
char test[N];
//...
while ( scanf("%9s", test) == 1 && strcmp(test, endword) != 0 ) {
And there are used redundantly too many variables like i, j and len.
The loop could be written simpler like
char test[N];
//...
for ( ; len < W && scanf("%9s", test) == 1 && strcmp(test, endword) != 0; ++len )
{
strcpy(words[len], test);
}
In this call
scanf("%d",position);
there is a typo. You must to write
scanf("%d", &position);
Also you should check whether the entered value of position is in the range [0, len].
For example
position = -1;
printf("\nPick the position\n");
scanf("%d", &position);
if ( len < W && -1 < position && position <= len ) {
Also this for loop
for (i = 0; i < W-1; i++) {
strcpy(words[i], words[i + 1]); /*Shift the words */
words[position] = newword;
}
does not make a sense. And moreover this assignment statement
words[position] = newword;
is invalid. Arrays do not have the assignment operator.
You need to move all strings starting from the specified position to the right.
For example
for ( i = len; i != position; --i )
{
strcpy( words[i], words[i-1] );
}
strcpy( words[position], newword );
++len;
And it seems the function convert_tolower should be called for the result array after inserting a new word. And moreover you need to pass the number of actual words in the array.
convert_tolower(words, len);
The nested loops within the function convert_tolower should look at least the following way
void convert_tolower(char matrix[][N], int n) {
int i;
int j;
for (i = 0; i < n; i++) {
for (j = 0; matrix[i][j] != '\0'; j++) {
matrix[i][j] = tolower(( unsigned char )matrix[i][j]);
}
}
}
The main problem with your code was initially that you declared char *words[W][N], then tried to insert strings into this 2d array of pointers. Sparse use of organizing functions, and variables with large scopes than necessary made it hard to read. I think the best way to help you is to show you a working minimal implementation. Step 4 is not sufficiently specified. insert currently shift. It is not clear what should happen if you insert at position after empty slots, or if insert a position before empty slots and in particular if there are non-empty slots after said position.
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#define W 5
#define N 10
void convert(size_t w, size_t n, char list[][n]) {
for(size_t i = 0; i < w; i++) {
for(size_t j = 0; j < n; j++) {
list[i][j] = tolower(list[i][j]);
}
}
}
void insert(size_t w, size_t n, char list[][n], size_t pos, char *word) {
// out out of bounds
if(pos + 1 > w) return;
// shift pos through w - 2 pos
for(size_t i = w - 2; i >= pos; i--) {
strcpy(list[i + 1], list[i]);
if(!i) break;
}
// insert word at pos
strcpy(list[pos], word);
}
void print(size_t w, size_t n, char list[][n]) {
for (size_t i = 0; i < w; i++) {
printf("%u: %s\n", i, list[i]);
}
}
int main() {
char words[W][N] = { "a", "BB", "c" };
convert(W, N, words);
insert(W, N, words, 0, "start");
insert(W, N, words, 2, "mid");
insert(W, N, words, 4, "end");
insert(W, N, words, 5, "error")
print(W, N, words);
return 0;
}
and the output (note: "c" was shifted out as we initially had 3 elements and added 3 new words with valid positions):
0: start
1: a
2: mid
3: bb
4: end
I want to remove all the repeated characters from array. here is example.
"aabccdee"
"bd"
I'm doing this C language. use only array, loop, if,else(conditional statements) not using pointer.
#include<stdio.h>
int main() {
char c[10];
char com[10] = {0,};
char result[10] = { 0, };
int cnt = 0;
for (int i = 0; i < 10; i++) {
scanf("%c", &c[i]);
}
for (int i = 0; i < 10; i++) {
for (int j = i+1; j < 10; j++) {
if (c[i] == c[j]) {
com[i] = c[i];
cnt++;
printf("%c", com[i]);
}
}
}
for (int i = 0; i < cnt; i++) {
for (int j = 0; j < 10; j++) {
if (com[i] != c[j]) {
result[j] = c[j];
}
}
}
printf("\n");
for (int i = 0; i < 10; i++) {
printf("%c", result[i]);
}
}
I thought this
Make repeated array
Compare original array to repeated array
Output
But repeated array loop can't looping all original array.
How can I do remove all repeated character?
Not good SO policy to blatantly answer homework, but I rarely do it and thought this was an interesting task. Certainly making no claims on efficiency, but it looks like it works to me. As far as I can tell, the first and last cases are corner cases, so I handle those individually, and use a loop for everything in the middle. If you're not allowed to use strlen, then you can roll your own or use some other method, that's not the primary focus of this problem (would be best to fgets the string from a command line argument).
#include <stdio.h>
#include <string.h>
int main(void)
{
char source[] = "aabccdee";
char result[sizeof(source)] = { 0 };
unsigned resultIndex = 0;
unsigned i = 0;
// do this to avoid accessing out of bounds of source.
if (strlen(source) > 1)
{
// handle the first case, compare index 0 to index 1. If they're unequal, save
// index 0.
if (source[i] != source[i+1])
{
result[resultIndex++] = source[i];
}
// source[0] has already been checked, increment i to 1.
i++;
// comparing to strlen(source) - 1 because in this loop we are comparing the
// previous and next characters to the current. Looping from 1 to second-to-the-
// last char means we stay in bounds of source
for ( ; i < strlen(source) - 1; i++)
{
if (source[i-1] != source[i] && source[i] != source[i+1])
{
// write to result if curr char != prev char AND curr char != next char
result[resultIndex++] = source[i];
}
}
// handle the end. At this point, i == the last index of the string. Compare to
// previous character. If they're not equal, save the last character.
//
if (source[i] != source[i-1])
{
result[resultIndex] = source[i];
}
}
else if (strlen(source) == 1)
{
// if source is only 1 character, then it's trivial
result[resultIndex] = source[i];
}
else
{
// source has no length
fprintf(stderr, "source has no length.\n");
return -1;
}
// print source and result
printf("source = %s\n", source);
printf("result = %s\n", result);
return 0;
}
Various outputs for source:
source = "aabccdee"
result = "bd"
source = "aaee"
result =
source = "a"
result = "a"
source = "abcde"
result = "abcde"
source = "abcdee"
result = "abcd"
source = "aabcde"
result = "bcde"
source = "aaaaaaaaaaaabdeeeeeeee"
result = "bd"
source = ""
source has no length.
first of all before we speak , you have to check this
you need to put a whitespace when scaning a char using scanf
so
scanf("%c", &c[i]);
becomes
scanf(" %c", &c[i]);
secondly your idea is kinda a messy as the result showed you're only handling cases and it doesn't continue verifying the whole array . you need to learn how to shift an array to the right or left
your issue later on that when you shift your table(not completely) you still print out of the size .
so bascilly in general your code should be something like this :
#include<stdio.h>
int main() {
char c[10];
int length=5;
for (int i = 0; i < 5; i++) {
scanf(" %c", &c[i]);
}
int j,k,i;
for(i=0; i<length; i++)
{
for(j=i+1; j<length; j++)
{
if(c[i] == c[j])
{
length--;
for(k=j; k<length; k++)
{
c[k] = c[k + 1];
}
j--;
}
}
}
printf("\n");
for (int i = 0; i < length; i++) {
printf("%c", c[i]);
}
}
you simply take one case and compare it to the rest , if it exists you shift from the position you find for the second time the element and so on
Here is my code. I need to find out the number of times a given word(a short string) occurs in a sentence(a long string).
Sample Input: the
the cat sat on the mat
Sample Output: 2
For some reason the string compare function is not working and my output is coming as zero. Kindly ignore the comments in the code as they have been put to debug the code.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){
char word[50];
gets(word);
int len = strlen(word);
//printf("%d",len);
char nword[len];
char s[100];
strcpy(nword,word);
puts(nword);
printf("\n");
gets(s);
//printf("%d",strlen(s));
char a[50][50];
int i,j,k;
j = 0;
for(i=0;i<strlen(s);i++)
{
a[i][j] = s[i];
printf("%c",a[i][j]);
if(s[i] == ' ')
{
j++;
printf("\n");
}
}
printf("%d",j);
k = j;
//printf("\nk assigned\n");
j = 0;
//printf("j equal to zero\n");
int count = 0;
int temp = 0;
//printf("count initialized.\n");
for(i=0;i<k;i++)
{
if(strcmp(a[i],nword) == 0)
count++;
}
printf("\n%d",count);
return 0;
}
Your main problem is with this loop for numerous reasons
int i,j,k;
j = 0;
for(i=0;i<strlen(s);i++)
{
a[i][j] = s[i];
printf("%c",a[i][j]);
if(s[i] == ' ')
{
j++;
printf("\n");
}
}
Firstly you've got your indexes into a backwards - a[i][j] means the i-th string and the j-th character, but since you're incrementing j for each word you want it the other way around - a[j][i].
Secondly you can't use i for both indexing into s and a. Think about what happens when you are building the second string. In your example input the second word starts when i is 4 so the first character will be stored as a[1][4]=s[4] which leaves a[1][0] to a[1][3] uninitialised. So you have to use a 3rd variable to track where you are in the other string.
When you hit a space, you don't want to add it to your word as it won't match later on. You also need to add in a null-terminator character to the end of each string or else your code won't know where the end of the string is.
Putting the above together gives you something like this:
int i,j,k;
k = j = 0;
for(i=0;i<strlen(s);i++)
{
if(s[i] == ' ')
{
a[j][k] = '\0';
j++;
k=0;
printf("\n");
}
else
{
a[j][k] = s[i];
printf("%c",a[j][k]);
k++;
}
}
a[j][k]='\0';
The problem is that a is a two-dimentional array and you reference it as a one dimention. Maby you use a 2-dimentional array to represent i=line, j=character. If you keep this idea then you'll have to do this:
j=0;
for(i=0;i<k;i++)
{
if(strcmp(a[i][j],nword) == 0)
count++;
j++;
}
But then it will be difficult to detect words that are split in half. I'd recommend keeping a as a one dimentional array. Copy the contents of s[i] serially and when you want to distinguish lines use the \r\n operator.
I think you use your 2-dimensional array wrong. a[0][j] should be the first word from s[i]. But what you are doing is a[i][0] = s[i] which makes no sense to me.
Best regards
I would implement this using the functions strtok() and strcmp():
int main(void)
{
char word[] = "the"; /* the word you want to count*/
char sample[] = "the cat sat on the mat"; /* the string in which you want to count*/
char delimiters[] = " ,;.";
int counter;
char* currentWordPtr;
/* tokenize the string */
currentWordPtr = strtok(sample, delimiters);
while(currentWordPtr != NULL)
{
if(strcmp(word, currentWordPtr) == 0)
{
counter++;
}
/* get the next token (word) */
currentWordPtr = strtok(NULL, delimiters);
}
printf("Number of occurences of \"%s\" is %i\n", word, counter);
return 0;
}
My assignment is to allow the user to enter any input and print the occurrences of letters and words, we also have to print out how many one letter, two, three, etc.. letter words are in the string. I have gotten the letter part of my code to work and have revised my word function several times, but still can't get the word finding function to even begin to work. The compiler says the char pointer word is undeclared when it clearly is. Do I have to allocate memory to it and the array of characters?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void findLetters(char *ptr);
void findWords(char *point);
int main()
{
char textStream[100]; //up to 98 characters and '\n\ and '\0'
printf("enter some text\n");
if (fgets(textStream, sizeof (textStream), stdin)) //input up to 99 characters
{
findLetters(textStream);
findWords(textStream);
}
else
{
printf("fgets failed\n");
}
return 0;
}
void findLetters(char *ptr) //find occurences of all letters
{
int upLetters[26];
int loLetters[26];
int i;
int index;
for (i = 0; i < 26; i++) // set array to all zero
{
upLetters[i] = 0;
loLetters[i] = 0;
}
i = 0;
while (ptr[i] != '\0') // loop until prt[i] is '\0'
{
if (ptr[i] >= 'A' && ptr[i] <= 'Z') //stores occurrences of uppercase letters
{
index = ptr[i] - 'A';// subtract 'A' to get index 0-25
upLetters[index]++;//add one
}
if (ptr[i] >= 'a' && ptr[i] <= 'z') //stores occurrences of lowercase letters
{
index = ptr[i] - 'a';//subtract 'a' to get index 0-25
loLetters[index]++;//add one
}
i++;//next character in ptr
}
printf("Number of Occurrences of Uppercase letters\n\n");
for (i = 0; i < 26; i++)//loop through 0 to 25
{
if (upLetters[i] > 0)
{
printf("%c : \t%d\n", (char)(i + 'A'), upLetters[i]);
// add 'A' to go from an index back to a character
}
}
printf("\n");
printf("Number of Occurrences of Lowercase letters\n\n");
for (i = 0; i < 26; i++)
{
if (loLetters[i] > 0)
{
printf("%c : \t%d\n", (char)(i + 'a'), loLetters[i]);
// add 'a' to go back from an index to a character
}
}
printf("\n");
}
void findWords(char *point)
{
int i = 0;
int k = 0;
int count = 0;
int j = 0;
int space = 0;
int c = 0;
char *word[50];
char word1[50][100];
char* delim = "{ } . , ( ) ";
for (i = 0; i< sizeof(point); i++) //counts # of spaces between words
{
if ((point[i] == ' ') || (point[i] == ',') || (point[i] == '.'))
{
space++;
}
}
char *words = strtok(point, delim);
for(;k <= space; k++)
{
word[k] = malloc((words+1) * sizeof(*words));
}
while (words != NULL)
{
printf("%s\n",words);
strcpy(words, word[j++]);
words = strtok(NULL, delim);
}
free(words);
}
This is because you are trying to multiply the pointer position+1 by the size of pointer. Change line 100 to:
word[k] = malloc(strlen(words)+1);
This will solve your compilation problem, but you still have other problems.
You've got a couple of problems in function findWords:
Here,
for (i = 0; i< sizeof(point); i++)
sizeof(point) is the same as sizeof(char*) as point in a char* in the function fincdWords. This is not what you want. Use
for (i = 0; i < strlen(point); i++)
instead. But this might be slow as strlen will be called in every iteration. So I suggest
int len = strlen(point);
for (i = 0; i < len; i++)
The same problem lies here too:
word[k] = malloc((words+1) * sizeof(*words));
It doesn't makes sense what you are trying with (words+1). I think you want
word[k] = malloc( strlen(words) + 1 ); //+1 for the NUL-terminator
You got the arguments all mixed up:
strcpy(words, word[j++]);
You actually wanted
strcpy(word[j++], words);
which copies the contents of words to word[j++].
Here:
free(words);
words was never allocated memory. Since you free a pointer that has not been returned by malloc/calloc/realloc, the code exhibits Undefined Behavior. So, remove that.
You allocated memory for each element of word. So free it using
for(k = 0; k <= space; k++)
{
free(word[k]);
}
Your calculation of the pointer position+1 is wrong. If you want the compilation problem will go away change line 100 to:
word[k] = malloc( 1 + strlen(words));
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;
}
Before the 2nd loop you want to set j=0. It should work after that.
PS: If you debugged by printing out your three strings, you would've figured it out in a matter of minutes. When you don't know what goes wrong, print out the values of variables at intermediate steps, so you know where your problem occurs and what it is.
Your question has already been answered by others but I'm posting this code to show that it is not necessary to make the phrase3 copy to hold the reversed string.
#include <stdio.h>
#include <string.h>
int main()
{
int i, j, length, halfLength;
char space = ' ';
char phrase1[80], phrase2[80];
printf("Give me the phrase: ");
gets(phrase1);
length = strlen(phrase1);
for( i = 0, j = 0; i <= length; ++i ) {
if( phrase1[i] != space ) { //Makes the phrase1 without spaces
phrase2[j++] = phrase1[i];
}
}
length = strlen(phrase2);
halfLength = length / 2;
for( i = 0, j = length - 1; i < halfLength; ++i, --j ) {
if( phrase2[i] != phrase2[j] ) {
printf("It's not a palindrome\n");
return 0;
}
}
printf("It's a palindrome\n");
return 0;
}
This is what I came up with:
#include <stdio.h>
void main() {
char a[50],b[50];
int i=0,j,ele,test=0,x;
while((a[i]=getchar())!='\n') {
if(a[i]!=' ' && a[i]!=',') //do not read whitespaces and commas(for palindromes like "Ah, Satan sees Natasha")
i++;
}
a[i]='\0';
ele=strlen(a);
// Convert string to lower case (like reverse of Ava is avA and they're not equal)
for(i=0; i<ele; i++)
if(a[i]>='A'&&a[i]<='Z')
a[i] = a[i]+('a'-'A');
x = ele-1;
for(j=0; j<ele; j++) {
b[j] = a[x];
x--;
}
for(i=0; i<ele; i++)
if(a[i]==b[i])
test++;
if(test==ele)
printf("You entered a palindrome!");
else
printf("That's not a palindrome!");
}
Probably not the best way for palindromes, but I'm proud I made this on my own took me 1 hour :( lol
Why not use a std::stack? You will need two loops, each iterating the length of the input string. In the first loop, go through the input string once, pushing each character ont the stack. In the second loop, pop a character off the stack and compare it with the character at the index. If you get a mismatch before the loop ends, you don't have a palindrome. The nice thing with this is that you don't have to worry about the even/odd length corner-case. It will just work.
(If you are so inclined, you can use one stack (LIFO) and one queue (FIFO) but that doesn't substantially change the algorithm).
Here's the implementation:
bool palindrome(const char *s)
{
std::stack<char> p; // be sure to #include <stack>
for(int i = 0; s[i] != 0; i++)
p.push(s[i]);
for(int i = 0; s[i] != 0; i++)
{
if(p.top() != s[i])
return false; // not a palindrome!
p.pop();
}
return true;
}
Skipping spaces is left as an exercise to the reader ;)