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I have created the below program to detect the shortest word in a sentence for me. However, the result is not what I expected. I went through the code a few times and I still could not find the problem.
I would be very grateful if someone could lend me some help.
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
ssize_t find_short(const char *s);
int main(void)
{
char s[100] ="lets talk about C the best language";
printf("%zu", find_short(s));
}
ssize_t find_short(const char *s)
{
int n = strlen(s);
int smallest = n;
int counter = 0;
for (int i = 0; i <= n; i++)
{
if (s[i] == ' ' || s[i] == '\0')
{
if (counter <= smallest)
{
smallest = (ssize_t) counter;
counter = 0;
}
}
else
counter ++;
}
return smallest;
}
Thank you very much.
You reset counter only when counter is smallest than smallest. If a new word is shorter than any previous, it will be ignored.
ssize_t find_short(const char *s)
{
int n = strlen(s);
int smallest = n;
int counter = 0;
for (int i = 0; i <= n; i++)
{
if (s[i] == ' ' || s[i] == '\0')
{
if (counter <= smallest)
{
smallest = (ssize_t) counter;
// <-- not here
}
counter = 0; // < -- here
}
else
counter ++;
}
return smallest;
}
counter=0 should be outside the if statement
ssize_t find_short(const char *s)
{
int n = strlen(s);
int smallest = n;
int counter = 0;
for (int i = 0; i <= n; i++)
{
if (s[i] == ' ' || s[i] == '\0')
{
if (counter <= smallest)
{
smallest = (ssize_t) counter;
}
counter = 0;
}
else
counter ++;
}
return smallest;
}
Related
I'm having some problem with saveing the vaule of the longest fence.
I tried this:
int longestFence(char input [], int size)
{
int i , max = 0, count = 0;
for(i = 0; i < size ; i++)
{
if(input[i] == '|' && input[i] == '-')
{
count = 1;
}
if(input[i] != input[i + 1])
{
count++ - 1;
}
}
return count;
}
In practice, to detect is the fence is still valid, you just have to check if the current symbol is different or not than the previous one.
You also have to check if the current count is longer or not than the previous longest one.
Besides, I modified the random string generator: the current one is rather inefficient.
In addition, the string generated is not terminated by the Null character. I also modified it.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX 10
int longestFence (char input[], int size) {
if (size == 0) return 0;
int max_count = 0;
int count = 1;
for (int i = 1; i < size; ++i) {
if (input[i] != input[i-1]) {
count++;
} else {
if (count > max_count) max_count = count;
count = 1;
}
}
if (count > max_count) max_count = count;
return max_count;
}
int main() {
char string[MAX+1];
char symbols[] = {'|', '-'};
srand (time(NULL));
int length = rand() % (MAX+1);
for (int i = 0; i < length; ++i) {
int val = (rand() / 16) % 2;
string[i] = symbols[val];
}
string[length] = '\0';
printf ("String is: %s\n", string);
printf ("Longest fence = %d\n", longestFence (string, length));
return 0;
}
Sorry for such a mediocre question, but I ran into what seems to be a tiny problem, but simply can't get over it. For my task I have to take a line of string from a file, and put it into another file backwards, for example:
one two three
four five six
would be
three two one
six five four
My problem is, is that I'm getting
three two one
si five four
So basically the flaw is that there is a space character at the beginning of each line and the last letter of the last word is always missing. Here's my reverse function:
void reverse(char input[], int length, char output[]) {
char space = 32;
input[length - 1] = space;
int value = 0;
int i, k = 0, j;
for (i = 0; i <= length; i++) {
if (input[i] == space) {
for (j = i - 1; j >= k; j--, value++) {
output[value] = input[j];
}
if (j == -1) {
output[value] = space;
value++;
}
k = i;
}
}
char c = 0;
for (int i = 0, j = length - 1; i <= j; i++, j--) {
c = output[i];
output[i] = output[j];
output[j] = c;
}
}
What I'm doing is first reversing each word by character, and then the whole line. If someone could help me find the last bits that I've missed I would greatly appreciate it.
The flaws come from your approach:
why do you force a space at offset length - 1? If you read the line with fgets(), there is probably a newline ('\n') at the end of the line, but it might be missing at the end of the input, which would explain the x getting overwritten on the last line.
you should not modify the input buffer.
Here is a simplified version, along with a simple main function:
#include <stdio.h>
#include <string.h>
void reverse(const char *input, int length, char *output) {
int i, j, k, v;
for (i = k = v = 0;; i++) {
if (i == length || input[i] == ' ') {
for (j = i; j-- > k; v++) {
output[v] = input[j];
}
for (; i < length && input[i] == ' '; i++) {
output[v++] = ' ';
}
if (i == length) {
output[v] = '\0';
break;
}
k = i;
}
}
for (i = 0, j = length - 1; i < j; i++, j--) {
char c = output[i];
output[i] = output[j];
output[j] = c;
}
}
int main() {
char input[256];
char output[256];
while (fgets(input, sizeof input, stdin)) {
reverse(input, strcspn(input, "\n"), output);
puts(output);
}
return 0;
}
Output:
three two one
six five four
Here is a simpler reverse function that operates in one pass:
#include <string.h>
void reverse(const char *input, int length, char *output) {
int i, j, k, v;
for (i = k = 0, v = length;; i++) {
if (i == length || input[i] == ' ') {
for (j = i; j-- > k;) {
output[--v] = input[j];
for (; i < length && input[i] == ' '; i++) {
output[--v] = ' ';
}
if (v == 0) {
output[length] = '\0';
break;
}
k = i;
}
}
}
Replace input[length - 1] = space; with input[length] = space;
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I want to get string(including white spaces)input save to 2-dimensional array.
my code is this :
char a[10000][6];
scanf("%d", &n);
for (int i = 0;i < n;i++)
{
scanf("%[^\n]s", a[i]);
}
for (int i = 0;i < n;i++)
{
printf("%s\n", a[i]);
}
What I got that is wrong output.Please give me any suggestion!
Use
char a[10000][6];
scanf("%d",&n);
int i;
for (i = 0;i < n;i++)
{
scanf("%s",&a[i]);
}
I recently solved this question in my program. I came to the conclusion that the best way to read input from keyboard is to handle character one by one. You can use code below.:
bool in()
{
int i;
int a;
int len;
int max;
char *text[10000];
//change 'max' somehow here before loop
for(i = 0, len = 0; i < max; i++)
{
text[i] = NULL;
do
{
do
{
a = getchar();
}
while(a == '\n' && !text[i]);
if(text[i])
{
len = strlen(text[i]);
len++;
}
else
{
len = 1;
}
text[i] = realloc(text[i], sizeof(char)*(len+1));
if(!text[i])
{
printf("cant realloc\n");
return false;
}
if(a != '\n')
{
text[i][len-1] = (char) a;
text[i][len] = '\0';
}
else
{
text[i][len-1] = '\0';
}
}
while(a != '\n');
}
return true;
}
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How can I compare 2 strings with maximum length 100 and print the equal part of them, like:
STRING 1 : ABCDEFGHIJKLMNOP
STRING 2 : QWERABCDZXVBERTY
The equal parts of these strings are : ABCD
Please look if this program can help you. It takes the two strings as arguments from the command line.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int *substring(char *s, char *t) {
int strlen1 = strlen(s);
int strlen2 = strlen(t);
int len = strlen1 < strlen2 ? strlen1 : strlen2;
int i, j, k;
int longest = 0;
int **ptr = (int **) malloc(2 * sizeof(int *));
static int *ret;
ret = (int *) calloc(strlen1 + 1, sizeof(int));
for (i = 0; i < 2; i++)
ptr[i] = (int *) calloc(strlen2, sizeof(int));
k = 0;
for (i = 0; i < strlen1; i++) {
memcpy(ptr[0], ptr[1], strlen2 * sizeof(int));
for (j = 0; j < strlen2; j++) {
if (s[i] == t[j]) {
if (i == 0 || j == 0) {
ptr[1][j] = 1;
} else {
ptr[1][j] = ptr[0][j - 1] + 1;
}
if (ptr[1][j] > longest) {
longest = ptr[1][j];
k = 0;
ret[k++] = longest;
}
if (ptr[1][j] == longest) {
ret[k++] = i;
ret[k] = -1;
}
} else {
ptr[1][j] = 0;
}
}
}
for (i = 0; i < 2; i++)
free(ptr[i]);
free(ptr);
ret[0] = longest;
return ret;
}
int main(int argc, char *argv[]) {
int i, longest, *ret;
if (argc != 3) {
printf("usage: longest-common-substring string1 string2\n");
exit(1);
}
ret = substring(argv[1], argv[2]);
if ((longest = ret[0]) == 0) {
printf("There is no common substring\n");
exit(2);
}
i = 0;
while (ret[++i] != -1) {
printf("%.*s\n", longest, &argv[1][ret[i] - longest + 1]);
}
exit(0);
}
Test
./a.out ABCDEFGHIJKLMNOP QWERABCDZXVBERTY
ABCD
Compare two strings is a common skill which is very easy to find information. First you should read string.h library where you can find a lot of useful function in order to work with strings.
Then the first stupid algorithm is to compare each char of first string with the second and if it matches you add that char to the result.
But it would be smarter to order the two strings and then compare them, saving many comparisons.
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I wrote the following code block I have all the time error in the function find_brackets and calculation. can someone explain to me how to fix it. And the two functions will function together
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void find_brackets(char str[], int len);
void calculation(char str1);
int main(void) {
int len;
char str1[99];
char str[99]; // (4/2)
printf("Enter a math exercises: \n");
gets(str);
len = strlen(str);
find_brackets(str);
calculation(str1);
}
void find_brackets(str[], len) {
char str1[len];
int i, j;
for(i = 0; i < len; i++) {
if(str[i] == '(') {
i++;
while(str[i] != ')') {
str1[j] = str[i];
i++;
j++;
}
}
}
}
void calculation(str1[], len) {
char str[len];
char strp[len];
char str2[len];
char str3[len];
char *rev;
int i, k, j = 0, aPos, zPos;
int sum1, sum2;
float sum;
strcpy (str, str1);
strcpy (strp, str1);
aPos = zPos = -1;
for(i = 0; i < len; i++) {
if(str[i] == '+') {
aPos = i;
}
else if(str[i] == '/') {
zPos = i;
break;
}
}
if(aPos != -1 && zPos != -1) {
for(k = 0, i = zPos-1; i > aPos; --i, ++k) {
str2[k] = str[i];
}
}
rev = strrev(str2);
printf("%s\n", rev);
for(i = 0; i < len; i++) {
if(strp[i] == '/') {
while(strp[i+1] != '+') {
str3[j++] = strp[++i];
}
}
}
printf("%s\n", str2);
sum1 = atoi(str2);
sum2 = atoi(str3);
sum = sum1 / sum2;
printf("%.0f\n", sum);
}
Thanks for the help I appreciate it
Function declaration is void find_brackets(char str[], int len); and the caller from main() is find_brackets(str); which is wrong. Where is the 2nd arg.
Also function calculation() has differnce in declaration and how it is invoked. Maintain a match in function formal arguments followed by callee actual arguments passed.
void find_brackets(str[],len)
void calculation(str1[],len)
please specify data type of len and str[] at function definations.
Also
find_brackets(str);
calculation(str1);
which pass one argument but you declared that with two which is also wrong.