Formatting output of a binary search using printf in C? - c

Question

I'm having some trouble with the output of this program. I need to print the verbs on one line, and I need to print a separate statement in the case that there are no verbs. For ex.
"talk and walk" should print "The verbs are: talk walk"
while "hello there" should print "There are no verbs"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int binary_search(char *list_of_words[], int size, char *target){
int bottom= 0;
int mid;
int top = size - 1;
int found = 0;
while(bottom <= top && !found){
mid = (bottom + top)/2;
if (strcmp(list_of_words[mid], target) == 0){
//printf("%s found at location %d.\n", target, mid+1);
found = 1;
} else if (strcmp(list_of_words[mid], target) > 0){
top = mid - 1;
} else if (strcmp(list_of_words[mid], target) < 0){
bottom = mid + 1;
}
}
if (found == 1)
return mid;
else
return -1;
}
int main(int argc, char* argv[]){
char *input = strtok(argv[1], " \"\n");
char *verbs[5] = { "do", "make", "take", "talk", "walk" };
int position;
int check = 0;
while (input != NULL) {
//printf("%s\n", input);
position = binary_search(verbs, 5, input);
if (position != -1)
printf("The verbs are: %s\n", verbs[position]);
check = 1;
input = strtok(NULL, " ");
}
if (check == 0){
printf("There are no verbs\n");
}
return 0;
}
Any ideas?

Answer 1

It seems to be working fine, but you need to add parenthesis around
if (position != -1)
printf("The verbs are: %s\n", verbs[position]);
check = 1;
like in
if (position != -1) {
printf("The verbs are: %s\n", verbs[position]);
check = 1;
}
otherwise check is always set 1 in the loop.
And if you do not want to repeat "The verbs are:" , add a check for that
if (position != -1) {
if (first) {
printf("The verbs are:");
first = 0;
check = 1;
}
printf(" %s", verbs[position]);
}

Answer 2

int main(int argc, char* argv[]){
char *input = strtok(argv[1], " \"\n");
char *verbs[5] = { "do", "make", "take", "talk", "walk" };
char match[5] = {0};
int position;
int check = 0;
while (input != NULL) {
//printf("%s\n", input);
position = binary_search(verbs, 5, input);
if (position != -1){
//printf("The verbs are: %s\n", verbs[position]);
match[position]=1;//match[position] = check = 1;
check = 1;
}
input = strtok(NULL, " ");
}
if (check == 0){
printf("There are no verbs\n");
} else {
int i;
printf("The verbs are: ");
for(i=0;i<5;++i)
if(match[i])
printf("%s ", verbs[i]);
printf("\n");
}
return 0;
}

Answer 3

If you're more interested in just having the search done, rather than implementing it yourself (i.e., assuming "implement a search" is not your actual task), you should use the standard library's little-known hero, bsearch().
Note that this requires the input data (the array you're searching in) to be sorted, but yours seems to be since you're already working on a binary search.