I am trying to get a string from the user, then remove all characters in a string, except the alphabets.
The string a string containing whitespace.
I have input a string, but the output is only "##".
I don't know what's happening.
//C program
//Program to remove all characters in a string, except alphabet
#include <stdio.h>
#include <string.h>
int main()
{
char str[150], copy[150];
int i = 0, j = 0;
printf("\nEnter a string : ");
fgets(str,150,stdin);
for (i = 0; i < 150; i++)
{
if ((str[i] >= 'a' && str[i] <= 'z') ||
(str[i] >= 'A' && str[i] <= 'Z') || (str[i] == '\0') )
{
*(copy + j) == *(str+i);
j++;
}
}
printf("\nResultant String : ");
for (int i = 0; i < strlen(str); i++)
{
printf("%c",copy[i]);
}
printf("\n");
return 0;
}
On terminal this is the program being run, I input "1 2 3 4 get on the dance floor".
Enter a string : 1 2 3 4 get on the dance floor
Resultant String : ##
The main problem is you're not doing an assignment here:
*(copy + j) == *(str+i);
The == is for comparison. You want =:
*(copy + j) = *(str+i);
Your loop conditions are also incorrect:
for (i = 0; i < 150; i++)
...
for (int i = 0; i < strlen(str); i++)
For the first loop, you're reading all bytes in the source array instead of just the ones that were set, and in the second one you're using the length of the source string instead of the result string to print the result. These should be:
for (i = 0; i < strlen(str); i++)
...
for (int i = 0; i < strlen(copy); i++)
Related
so this is my function. My main focus is to get the character frequencies and the highest character frequency.
The function below (get_letter_frequencies) is supposed to get a string example ("I am a big boy") and return the character frequencies and the highest character frequency.
The Function should return
i - 2
a - 2
m - 1
b - 2
g - 1
o - 1
y - 1
Highest character frequency would be " iab "
My problem is with the get_letter_frequencies function. What should I arrange from the function in order to return the above output?
void get_letter_frequencies(const char *text, size_t len, int freq[26], int *max_freq)
{
for(int i = 0; i<len; i++)
{
if(text[i] != ' ' || !(is_sentence_terminator(text[i]))) //this condition is set in order to ignore the spaces and the sentence terminators (! ? .)
{
if(text[i] >= 'a' && text[i] <= 'z')
{
freq[text[i] - 'a']++;
}
}
}
for(int j = 0; j < 26; j++)
{
if(freq[j] >= 1)
{
*max_freq = freq[j];
}
}
This function below(is_sentence_terminator). Here the function checks whether the sentence finishes with a " ! ? or . " if it does not finish with one of the terminators then it is not a sentence and ignores it.
int is_sentence_terminator(char ch)
{
if(ch == 33 || ch == 46 || ch == 63)
{
return 1;
}else
{
return 0;
}
}
There are some issues in your code:
there is no need to test for special characters, comparing text[i] to 'a' and 'z' is sufficient for ASCII systems.
in the second loop, you should update *max_freq only if freq[j] is greater than the current value, not 1. *max_freq should be initialized to 0 before the loop.
In the calling code, you would also
print the letters whose frequency is non 0.
print all letters with the maximum frequency using one final loop.
Here is a modified version:
void get_letter_frequencies(const char *text, size_t len, int freq[26], int *max_freq) {
for (int i = 0; i < 26; i++)
freq[i] = 0;
for (int i = 0; i < len; i++) {
if (text[i] >= 'a' && text[i] <= 'z') {
freq[text[i] - 'a']++; // assuming ASCII
}
}
*max_freq = 0;
for (int i = 0; i < 26; i++) {
if (*max_freq < freq[i]) {
*max_freq = freq[i];
}
}
}
I need to check if a given string is a Palindrome or mini-Palindrome.
Palindrome length will be 2 or more, the function need to ignore spaces and ignore the differences of upper and lower alphabet.
if the string is Palindrome the function will transfer the indexes of the start and the end of him and will return 1 else return 0.
example1: "My gym" the function will transfer low=0 high=5 and 1
example2: "I Love ANNA" the function will transfer low=7 high=10 and 1
example3: "I love Pasta" return 0.
Also i can’t use functions from librarys other then string.h stdlib.h stdio.h.
I tried to write like this:
int i;
int size = strlen(str);
i = 0;
while (str[i] != '\0')
{
if (str[i] == ' ')
{
i++;
continue;
}
//-------------------
if (str[i] >= ‘a’ && str[i] <= ‘z’)
str[i] = str[i] - 32;
if (str[size-1] >= ‘a’ && str[size-1] <= ‘z’)
str[size-1] = str[size-1] - 32;
//-------------------
if (str[i] == str[size-1])
{
*low = i;
*high = size-1;
return 1;
}
else
{
size--;
i++;
}
}
return 0;
But it isnt working well, i cant figure how to do it with the example 2
Here goes. Will this help you
#define LOWER(a) (((a) >=' A' && (a) <= 'Z') ? ((a) - 'A' +'a') : (a))
#define MYCMP(a,b) (LOWER(a) == LOWER(b))
int is_palidrome(char *s) {
int start = 0;
int end = strlen(s) - 1;
for (; s[start] // Not end of line
&& end >=0 // Not run over the from of the line
&& start < end // Still not got to the middle
&& MYCMP(s[start], s[end]) == 1; // They are still equal
start++, end--) { //Nowt }
};
return (start >= end);
}
I made a program. It works only if the string contains letters and spaces. You can modify it to work for other characters.
#include <stdio.h>
#include <string.h>
#define SIZE 100
int isPalindrome( char *s, size_t l );
int main() {
char str[SIZE];
size_t i, j, len, pldrm = 0;
fgets(str, SIZE, stdin);
len = strlen(str);
for(i = 0; i < len; i++) if( str[i] != ' ' && !((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z')) ) goto the_end;
for(i = 0; i < len-1; i++) {
if( str[i] != ' ' ) {
for(j = i+1; j < len; j++) {
if( (pldrm = isPalindrome(&str[i], j-i+1)) ) {
str[j+1] = '\0';
goto the_end;
}
}
}
}
the_end:
pldrm ? printf("A palindrome has been found from the position %zu till the position %zu.\n\nThe palindrome is: %s\n", i, j, &str[i]) : puts("No palindromes");
return 0;
}
int isPalindrome( char *s, size_t l )
{
static const char az[26] = "abcdefghijklmnopqrstuvwxyz", AZ[26] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int isPldrm = 1, spc = 0; // used to skip spaces within the palindrome
for(size_t i = 0; i < l/2; i++) {
for(size_t j = 0; j < 26; j++) {
if( s[i] == az[j] || s[i] == AZ[j] ) {
while( s[l-1-i-spc] == ' ' ) ++spc;
if( s[l-1-i-spc] != az[j] && s[l-1-i-spc] != AZ[j] ) {
isPldrm = 0;
goto thats_it;
}
break;
}
}
}
thats_it:
return isPldrm;
}
Also, it finds only the first palindrome in the input. Doesn't check for further palindromes.
I'm fairly new to coding and am currently enrolled in a course at school teaching C. We have been given an assignment that requires as follows:
Write a program that inputs three lines of text and uses the function strchr to determine the number of occurrences of each letter of the alphabet (uppercase and lowercase should be counted as the same). Store the totals for each letter in an array and print the result.
Here's the code I've written so far:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#define SIZE 100
int main(void) {
int alphabet[26] = { 0 };
char string[3][SIZE];
int i, j;
int c;
printf("Enter three lines of text:\n");
for (i = 0; i <= 2; i++) {
fgets(string[i], SIZE, stdin);
}
for (i = 0; i <= 2; i++) {
for (j = 0; &string[i][j] != '\0'; j++) {
string[i][j] = tolower(string[i][j]);
}
for (j = 0; &string[i][j] != '\0'; j++) {
if (strchr(&string[i][j], ('a' + j)) != NULL) {
alphabet[j]++;
}
}
}
printf("\n");
for (i = 0; i < 26; i++) {
printf("%c: %d\n", ('a' + i), alphabet[i]);
}
printf("\n");
return 0;
}
The problem with the current program I have is that the counter for the array alphabet[] doesn't seem to be incrementing the count properly.
The output should count, for example, increment by 1 for each occurrence of every letter, but the results are all 0.
Any other tips or words of advice are greatly appreciated!
Your test for end of line is wrong,
no need to loop several time just parse the string and count the letters
You want letter between 'a'and 'z', check if the char is in the range and count it
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#define SIZE 100
int main(void) {
int alphabet[26] = { 0 };
char string[3][SIZE];
int i, j;
printf("Enter three lines of text:\n");
for (i = 0; i <= 2; i++) {
fgets(string[i], SIZE, stdin);
}
for (i = 0; i <= 2; i++) {
for (j = 0; string[i][j] != '\0'; j++) {
char c = tolower(string[i][j]);
if (c >= 'a' && c <= 'z') {
alphabet[c - 'a']++;
}
}
}
printf("\n");
for (i = 0; i < 26; i++) {
printf("%c: %d\n", ('a' + i), alphabet[i]);
}
printf("\n");
return 0;
}
You need to change loop terminating condition from &string[i][j] != '\0'; to string[i][j] != '\0';
strchr will return the address from the string where match was found, so you should save the non null address to pass it to next call to strchr
Something like this:
tmpPtr = &string[i][j];
while ((tmpPtr=strchr(tmpPtr, string[i][j])) != NULL) {
alphabet[string[i][j] - 'a']++;
}
My program is designed to allow the user to input a string and my program will output the number of occurrences of each letters and words. My program also sorts the words alphabetically.
My issue is: I output the words seen (first unsorted) and their occurrences as a table, and in my table I don't want duplicates. SOLVED
For example, if the word "to" was seen twice I just want the word "to" to appear only once in my table outputting the number of occurrences.
How can I fix this? Also, why is it that i can't simply set string[i] == delim to apply to every delimiter rather than having to assign it manually for each delimiter?
Edit: Fixed my output error. But how can I set a condition for string[i] to equal any of the delimiters in my code rather than just work for the space bar? For example on my output, if i enter "you, you" it will out put "you, you" rather than just "you". How can I write it so it removes the comma and compares "you, you" to be as one word.
Any help is appreciated. My code is below:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
const char delim[] = ", . - !*()&^%$##<> ? []{}\\ / \"";
#define SIZE 1000
void occurrences(char s[], int count[]);
void lower(char s[]);
int main()
{
char string[SIZE], words[SIZE][SIZE], temp[SIZE];
int i = 0, j = 0, k = 0, n = 0, count;
int c = 0, cnt[26] = { 0 };
printf("Enter your input string:");
fgets(string, 256, stdin);
string[strlen(string) - 1] = '\0';
lower(string);
occurrences(string, cnt);
printf("Number of occurrences of each letter in the text: \n");
for (c = 0; c < 26; c++){
if (cnt[c] != 0){
printf("%c \t %d\n", c + 'a', cnt[c]);
}
}
/*extracting each and every string and copying to a different place */
while (string[i] != '\0')
{
if (string[i] == ' ')
{
words[j][k] = '\0';
k = 0;
j++;
}
else
{
words[j][k++] = string[i];
}
i++;
}
words[j][k] = '\0';
n = j;
printf("Unsorted Frequency:\n");
for (i = 0; i < n; i++)
{
strcpy(temp, words[i]);
for (j = i + 1; j <= n; j++)
{
if (strcmp(words[i], words[j]) == 0)
{
for (a = j; a <= n; a++)
strcpy(words[a], words[a + 1]);
n--;
}
} //inner for
}
i = 0;
/* find the frequency of each word */
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
}
}
}
/* count - indicates the frequecy of word[i] */
printf("%s\t%d\n", words[i], count);
/* skipping to the next word to process */
i = i + count;
}
printf("ALphabetical Order:\n");
for (i = 0; i < n; i++)
{
strcpy(temp, words[i]);
for (j = i + 1; j <= n; j++)
{
if (strcmp(words[i], words[j]) > 0)
{
strcpy(temp, words[j]);
strcpy(words[j], words[i]);
strcpy(words[i], temp);
}
}
}
i = 0;
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
}
}
}
printf("%s\n", words[i]);
i = i + count;
}
return 0;
}
void occurrences(char s[], int count[]){
int i = 0;
while (s[i] != '\0'){
if (s[i] >= 'a' && s[i] <= 'z')
count[s[i] - 'a']++;
i++;
}
}
void lower(char s[]){
int i = 0;
while (s[i] != '\0'){
if (s[i] >= 'A' && s[i] <= 'Z'){
s[i] = (s[i] - 'A') + 'a';
}
i++;
}
}
I have the solution to your problem and its name is called Wall. No, not the type to bang your head against when you encounter a problem that you can't seem to solve but for the Warnings that you want your compiler to emit: ALL OF THEM.
If you compile C code with out using -Wall then you can commit all the errors that people tell you is why C is so dangerous. But once you enable Warnings the compiler will tell you about them.
I have 4 for your program:
for (c; c< 26; c++) { That first c doesn't do anything, this could be written for (; c < 26; c++) { or perhaps beter as for (c = 0; c <26; c++) {
words[i] == NULL "Statement with no effect". Well that probably isn't what you wanted to do. The compiler tells you that that line doesn't do anything.
"Unused variable 'text'." That is pretty clear too: you have defined text as a variable but then never used it. Perhaps you meant to or perhaps it was a variable you thought you needed. Either way it can go now.
"Control reaches end of non-void function". In C main is usually defined as int main, i.e. main returns an int. Standard practice is to return 0 if the program successfully completed and some other value on error. Adding return 0; at the end of main will work.
You can simplify your delimiters. Anything that is not a-z (after lower casing it), is a delimiter. You don't [need to] care which one it is. It's the end of a word. Rather than specify delimiters, specify chars that are word chars (e.g. if words were C symbols, the word chars would be: A-Z, a-z, 0-9, and _). But, it looks like you only want a-z.
Here are some [untested] examples:
void
scanline(char *buf)
{
int chr;
char *lhs;
char *rhs;
char tmp[5000];
lhs = tmp;
for (rhs = buf; *rhs != 0; ++rhs) {
chr = *rhs;
if ((chr >= 'A') && (chr <= 'Z'))
chr = (chr - 'A') + 'a';
if ((chr >= 'a') && (chr <= 'z')) {
*lhs++ = chr;
char_histogram[chr] += 1;
continue;
}
*lhs = 0;
if (lhs > tmp)
count_string(tmp);
lhs = tmp;
}
if (lhs > tmp) {
*lhs = 0;
count_string(tmp);
}
}
void
count_string(char *str)
{
int idx;
int match;
match = -1;
for (idx = 0; idx < word_count; ++idx) {
if (strcmp(words[idx],str) == 0) {
match = idx;
break;
}
}
if (match < 0) {
match = word_count++;
strcpy(words[match],str);
}
word_histogram[match] += 1;
}
Using separate arrays is ugly. Using a struct might be better:
#define STRMAX 100 // max string length
#define WORDMAX 1000 // max number of strings
struct word {
int word_hist; // histogram value
char word_string[STRMAX]; // string value
};
int word_count; // number of elements in wordlist
struct word wordlist[WORDMAX]; // list of known words
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));