The following program runs without printing anything on the screen, maybe because the loop goes over the null character. I can't understand why and how this happens, and how to fix it.
//program to find how many word in the text doesn't contain p char
#include<stdio.h>
#include<stdbool.h>
#define space ' '
void find_word(char s[]) {
bool wordfound = false;
int i, j = 0, word = 0;
i = 0;
while (s[i]) { //s[i]!='\0' does not
if (s[i] != 'p' && s[i + 1] != space) { //for the first word
wordfound = true;
word++;
}
wordfound = false;
if (s[i] == space && s[i + 1] != space) { //for more than one word in the text
for (j = i + 1; s[j] != space; j++)
if (s[j] != 'p' && s[j + 1] != space)
wordfound = true;
}
if (wordfound) {
word++;
}
wordfound = false;
i = j;
i++;
} //end while loop
printf("Number of words not contain p character%d\n\n", word);
}
int main(void) {
char s[] = {"pppp zzzz ppp ssss dfg sfsfdsf"};
find_word(s);
return 0;
}
You appear to have your for-loop
terminating condition set to be unsatisfiable given your input.
if (s[i] == space && s[i + 1] != space) { //for more than one word in the text
for (j = i + 1; s[j] != space; j++)
if (s[j] != 'p' && s[j + 1] != space)
wordfound = true;
}
Here you are checking for a leading space in your input string. If you find it you then increment your index checking until you reach another space. What if your string doesn't have a trailing space?
Instead try to have a second condition for null and space to terminate the loop:
if (s[i] == space && s[i + 1] != space) { //for more than one word in the text
for (j = i + 1; s[j] != '\0' && [j] != space; j++)
if (s[j] != 'p' && s[j + 1] != space)
wordfound = true;
}
And then you set:
wordfound = false;
i = j;
i++;
} //end while loop
This will keep re-setting your loop, I'm not clear on your reasoning for this but that will run your loop indefinitely.
If you make these edits your code terminates:
#include<stdio.h>
#include<stdbool.h>
#define space ' '
void find_word(char s[]) {
bool wordfound = false;
int i, j = 0, word = 0;
i = 0;
while (s[i]) { //s[i]!='\0' does not
if (s[i] != 'p' && s[i + 1] != space) { //for the first word
wordfound = true;
word++;
}
wordfound = false;
if (s[i] == space && s[i + 1] != space) { //for more than one word in the text
for (j = i + 1; s[j] && s[j] != space; j++)
if (s[j] != 'p' && s[j + 1] != space)
wordfound = true;
}
if (wordfound) {
word++;
}
wordfound = false;
i++;
} //end while loop
printf("Number of words not contain p character%d\n\n", word);
}
int main(void) {
char s[] = {"pppp zzzz ppp ssss dfg sfsfdsf"};
find_word(s);
return 0;
}
Output:
Number of words not contain p character24
There are a few problems with this code, but the main one is that inside the loop you assign j to i which causes the infinite loop as the while(s[i]) condition is never met. Why don't you try to make it simple, like so:
//program to find how many word in the text doesn't contain p char
#include<stdio.h>
#include<stdbool.h>
#define space ' '
void find_word(char s[]) {
bool is_in = false;
short words_count = 0, i = 0;
while (s[i]) {
if (s[i] == 'p') { // if this letter is a 'p', mark the word
is_in = true;
}
if (s[i] == space) { // if it's end of word
if (!is_in) { // check if 'p' is present and increase the count
words_count++;
}
is_in = false;
}
i++;
}
if (!is_in) { // check if the last word has 'p'
words_count++;
}
printf("no. of words without p is %d\n", words_count);
}
int main(void) {
char s[] = {"pppp zzzz ppp ssss dfg sfsfdsf"};
find_word(s);
return 0;
}
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