i trying to make a palindrom out of the user input.
Im saving the user input as array in char eingabe[]
with int i im counting the index of the used arrays.
Then i want to copy the reversed value of eingabe in palindrom and then printf both of them to get the palindrom.
My i and j are counting correctly, but i dont get the output for palindrom.
I hope you can help me.
#include <stdio.h>
int main(){
char eingabe[20];
char palindrom[20];
int i = 0;
int j = 0;
char c;
do{
c = getchar();
if (c != EOF){
eingabe[i] = c;
i++;
}
} while (c != EOF);
eingabe[i] = '\0';
do{
palindrom[j] = eingabe[i];
j++;
--i;
} while (i != 0);
palindrom[j] = '\0';
printf("\n\n%s",eingabe);
printf("%s\n\n",palindrom);
return 0;
}
It is sometimes very helpful to add printf's to see what is going on. For example, if I add:
do {
printf("palindrom[%d] = eingabe[%d]\n", j, i);
palindrom[j] = eingabe[i];
then the output is:
abcde
palindrom[0] = eingabe[5]
palindrom[1] = eingabe[4]
palindrom[2] = eingabe[3]
palindrom[3] = eingabe[2]
palindrom[4] = eingabe[1]
eingabe: "abcde"
palindrom: ""
The problem is immediately obvious: the array index is off by 1. Since the first character of palindrom ([0]) gets set to the last character of eingabe ([5]) which is "\0", then C sees it as an empty string.
This is easily corrected by moving the --i to the top of the loop:
do {
--i;
palindrom[j] = eingabe[i];
j++;
} while (i != 0);
Try palindrom[j] = eingabe[i-1]; Instead.
even this will work:
i=0;
do{
palindrom[j++] = eingabe[i++];
} while ( eingabe[i]!='/0');
j=0;
do{
palindrom[j++] = eingabe[i--];
} while ([i]>0);
palindrom[j] = '\0';
Related
I have been working on a hangman game for my class which is due today and just now it decided to no longer provide any output from my code. If someone could please give it a look so I can go back to possibly submitting this assignment, I would be very appreciative. I dont know what changed specifically.
char **readWordList(char *, int *);
int main(int argc, char *argv[]) {
char **wordList;
char inputFile[100];
int count = 0;
int i;
if (argc != 2) {
printf("You need to provide the word list file name.\n ");
printf("Usage: $0 filename\n");
return -1;
}
wordList = readWordList(argv[1], &count); //function (target input[s], y placeholder var)
if (wordList == NULL) {
printf("Read word failed\n");
exit(1);
}
printf("fortnite");
int a = 0; //placeholder variables
int b = 0;
int c = 0;
int v = 0;
int g = 0;
int hit = 0;
srand(time(NULL)); //random variable for word selection
int r = rand() % 3;
int chances = 10;
char *word = wordList[r]; //address word from line.txt
char guess;
char misses[10];
int lettercount = 0;
//make blank variable by reading random accessed word
for (size_t a = 0; word[a] != 0; a++) {
lettercount++;
}
char space[lettercount];
// write underscores in place of spaces in temporary array
for (size_t c = 0; word[c] != '\0'; c++) {
space[c] = 95;
}
char blank[lettercount * 2]; //equal to array size empty array
// borrowing my spacename function, but seems to make artifacts in blank input now
int t = 0;
int k = 0;
while (space[t] != '\0') {
k = 2 * t;
if (k > lettercount * 2 - 2) {
blank[k] = space[t];
break;
}
blank[k] = space[t];
blank[k + 1] = ' ';
}
while (chances > 0) {
printf("Chances:%d\n", chances);
printf("Misses:%d\n", misses);
printf("Word:%s\n", blank);
printf("Guess[Q]:");
scanf("%c\n", &guess);
while (word[b] != '\0') {
if (guess = 'Q') {
exit(0);
}
if (guess = word[b]) {
v = b * 2;
blank[v] = guess;
b++;
hit = 1;
}
b++;
}
if (hit != 1) {
misses[g] = guess;
}
if (hit = 1) {
hit = 0;
}
chances--;
g++;
}
}
There are multiple problems in the code, including some serious ones:
the #include lines are missing.
the readWordList function is missing.
if (guess = 'Q') sets guess to 'Q' and evaluates to true. You should write if (guess == 'Q')
if (guess = word[b])... same problem.
printf("Misses:%d\n", misses); should be printf("Misses:%s\n", misses); and misses should be initialized as the empty string.
printf("Word:%s\n", blank); has undefined behavior as blank is not null terminated.
while (space[t] != '\0') may iterate too far as space does not have a null terminator since it's length is lettercount and all elements have been set to 95 ('_' in ASCII). Yet since you never increment t, you actually have an infinite loop. Use a simple for loop instead: for (t = 0; i < lettercount; t++)
scanf("%c\n", &guess); reads a character and consumes any subsequent white space, so the user will have to type another non space character and a newline for scanf() to return. You should instead use scanf(" %c", &guess);
while (word[b] != '\0') will iterate beyond the end of the array after the first guess because you do not reset b to 0 before this loop. Furthermore, b is incremented twice in case of a hit. You should use for loops to avoid such silly mistakes.
if (hit = 1) { hit = 0; }... the test is incorrect (it should use ==) and you could just write hit = 0; or better set hit to 0 before the inner loop.
inputFile is unused.
You should compile with gcc -Wall -Wextra -Werror to avoid such silly bugs that can waste precious time.
i fixed it, i lost a variable which provided the chance that a while loop would end for the spacing array function
sorry for being annoying
I am creating a program where I insert a number of sentences and the program outputs them in order. I have finished the program, but when I run it it seems like the characters I input into the array aren't displayed or stored correctly, getting as a result random letters instead of the full sentence. Here is the code of the program:
char ch;
int i,j,k;
int nothing = 0;
int count = 1;
char lines[5][256];
int length[256];
int main() {
printf("Please insert up to a max of 5 lines of text (Press enter to go to next line and twice enter to stop the program):\n");
i = 0;
while (i<5){
j = 0;
ch = getche();
if (ch == '\r'){
if(i!= 0){
break;
}
printf("You have not inserted anything, please insert a line:");
i=-1;
}
if(ch != '\r'){
lines[i][j]=ch;
while (ch!='\r'){
ch = getche();
lines[i][j] = ch;
j++;
}
}
printf("\n");
i++;
}
for (k=i ; k > 0; k--){
printf("\tphrase %i :", count);
for ( j =0 ; j <= length[k]; j++){
printf("%c",lines[j][k]);
}
count++;
printf("\n");
}
return 0;
}
How can I get the characters to be stored and displayed correctly? Any help is appreciated, thank you!!
There are numerous problems with your code. I'll try and summarise here, and give you improved code.
Fist, some changes that I made to get this to compile on my system:
Changed getche() to getchar() (getche() does not appear to be available on Ubuntu).
I took out the section about re-entering a string, and just focused on the rest (since the logic there was slightly broken, and not relevant to your question). It will still check for at least one line though, before it will continue.
I had to change the check for \r to \n.
I changed your length array to size 5, since you'll only have the lengths of maximum 5 strings (not 256).
Some problems in your code:
You never updated the length[] array in the main while loop, so the program never knew how many characters to print.
Arrays are zero indexed, so your final printing loops would have skipped characters. I changed the for parameters to start at zero, and work up to k < i, since you update i after your last character in the previous loop. The same with j.
Your reference to the array in the printing loop was the wrong way around (so you would've printed from random areas in memory). Changed lines[j][k] to lines[k][j].
No need for a separate count variable - just use k. Removed count.
The nothing variable does not get used - removed it.
#include <stdlib.h>
#include <stdio.h>
char ch;
int i,j,k;
char lines[5][256];
int length[5];
int main()
{
printf("Please insert up to a max of 5 lines of text (Press enter to go to the next line and twice enter to stop the program):\n");
i = 0;
while (i<5)
{
j = 0;
ch = getchar();
if ((ch == '\n') && (j == 0) && (i > 0))
{
break;
}
if (ch != '\n')
{
while (ch != '\n')
{
lines[i][j] = ch;
j++;
ch = getchar();
}
}
length[i] = j;
printf("\n");
i++;
}
for (k = 0; k < i; k++)
{
printf("\tPhrase %i : ", k);
for (j = 0; j < length[k]; j++)
{
printf("%c", lines[k][j]);
}
printf("\n");
}
return 0;
}
I'm trying to create a C program that accepts a line of characters from the console, stores them in an array, reverses the order in the array, and displays the reversed string. I'm not allowed to use any library functions other than getchar() and printf(). My attempt is below. When I run the program and enter some text and press Enter, nothing happens. Can someone point out the fault?
#include <stdio.h>
#define MAX_SIZE 100
main()
{
char c; // the current character
char my_strg[MAX_SIZE]; // character array
int i; // the current index of the character array
// Initialize my_strg to null zeros
for (i = 0; i < MAX_SIZE; i++)
{
my_strg[i] = '\0';
}
/* Place the characters of the input line into the array */
i = 0;
printf("\nEnter some text followed by Enter: ");
while ( ((c = getchar()) != '\n') && (i < MAX_SIZE) )
{
my_strg[i] = c;
i++;
}
/* Detect the end of the string */
int end_of_string = 0;
i = 0;
while (my_strg[i] != '\0')
{
end_of_string++;
}
/* Reverse the string */
int temp;
int start = 0;
int end = (end_of_string - 1);
while (start < end)
{
temp = my_strg[start];
my_strg[start] = my_strg[end];
my_strg[end] = temp;
start++;
end--;
}
printf("%s\n", my_strg);
}
It seems like in this while loop:
while (my_strg[i] != '\0')
{
end_of_string++;
}
you should increment i, otherwise if my_strg[0] is not equal to '\0', that's an infinite loop.
I'd suggest putting a breakpoint and look what your code is doing.
I think you should look at your second while loop and ask yourself where my_string[i] is being incremented because to me it looks like it is always at zero...
void main()
{
int i, j, k,flag=1;
char key[10], keyword[10];
gets(key);
i=0;
j=0;
while(key[i]!='\0') {
k=0;
while(keyword[k]!='\0') {
if(key[i]==keyword[k]) {
i++;
flag=0;
break;
}
k++;
}
if(flag==1) {
keyword[j]=key[i];
j++;
i++;
}
flag=1;
}
}
Here I tried to copy unique alphabets from array to another array ..means duplicate alphabet should not copied in another array..it shows right output but along with that it shows some garbage values like smiley or something till the length of original input array(i.e.key[])
You need to add a terminator to the unique character string both at the time it is initialized, and every time a new letter is added:
#include <stdio.h>
int main() {
int i = 0, j = 0;
char redundant[10], unique[10] = { '\0' };
gets(redundant);
while (redundant[i] != '\0') {
int k = 0, flag = 1;
while (unique[k] != '\0') {
if (redundant[i] == unique[k]) {
flag = 0;
break;
}
k++;
}
if (flag) {
unique[j++] = redundant[i];
unique[j] = '\0';
}
i++;
}
printf("%s -> %s\n", redundant, unique);
return(0);
}
OUTPUT
% ./a.out
warning: this program uses gets(), which is unsafe.
aardvark
aardvark -> ardvk
%
Now let's consider a different approach that wastes some space to simplify and speed up the code:
#include <stdio.h>
#include <string.h>
int main() {
unsigned char seen[1 << (sizeof(char) * 8)] = { 0 }; // a flag for every ASCII character
char redundant[32], unique[32];
(void) fgets(redundant, sizeof(redundant), stdin); // gets() is unsafe
redundant[strlen(redundant) - 1] = '\0'; // toss trailing newline due to fgets()
int k = 0; // unique character counter
for (int i = 0; redundant[i] != '\0'; i++) {
if (!seen[(size_t) redundant[i]]) {
unique[k++] = redundant[i];
seen[(size_t) redundant[i]] = 1; // mark this character as seen
}
}
unique[k] = '\0'; // terminate the new unique string properly
printf("%s -> %s\n", redundant, unique);
return 0;
}
Instead of a second, inner loop to search if a letter has been copied already, we use an array of flags (boolean), where the letter is the index, to determine if the letter has been processed.
Another thing you might want to think about is whether to treat upper and lower case differently or fold them into one.
i want to write code in c language to delete any character in string s1 which matches any character in the string s2 . using only for loops. that is my trial has failed -_- .
for example if s1="ahmed" and s2="omnia" should edit s1 to >> s1="hed"
#include <stdio.h>
#include <stdlib.h>
int i,j;
int k;
int counter=0;
int main()
{
char s1[100];
char s2[10];
char temp[100];
printf("\n enter string 1: ");
scanf("%s",s1);
printf("\n enter string 2: ");
scanf("%s",s2);
printf("\n%s",s1);
printf("\n%s",s2);
for(j=0;j<9;j++)
{
for(i=0;i<9;i++)
{
if(s1[i]!=s2[j]&&s1[i]!='\0')
{
temp[counter++]=s1[i]; //add unique items to temp
k=counter; //size
temp[counter]='\0';
}
}
}
for(i=0;i<k;i++)
{
s1[i]=temp[i];
}
printf("\nstring 1 after delete : ");
printf("%s",s1);
return 0;
}
how can i compare one item with nested items then achieve a condition ??
Why are you including the null character statements inside the if statement?
Try these two statements after the two for loops, like this. And please indent your code.
for(j=0;j<strlen(s1);j++) //Why is it 9 in your code? It should be the respective lengths
{
for(i=0;i<strlen(s2);i++)
{
if(s1[i]!=s2[j]&&s1[i]!='\0')
{
temp[counter++]=s1[i];
}
}
}
k=counter;
temp[counter]='\0';
and include:#include<string.h>
I don't see any coding errors here, only your logic is flawed.
This should work
for (j = 0; j < 9; j++)
{
for (i = 0; i < 9; i++)
{
if (s1[j] == s2[i] && s1[i] != '\0')
{
break;
}
else if (i == strlen(s2))
{
temp[counter++] = s1[j];
}
}
}
temp[counter] = '\0';
for (i = 0; i < counter; i++)
{
s1[i] = temp[i];
}
printf("\nstring 1 after delete : ");
printf("%s", s1);
In your original code you kept reading the original string from the beginning, instead of advancing the iterator each time.
So in the first iteration you compared 'ahmed' against 'omnia' which is fine.
In the second iteration though, you compared 'ahmed' against 'omnia', instead of 'hmed' against 'omnia', and that's why you got a large repetition of the original string in your output.
Also, I'd memset the memory of s1 and s2 first to 0.