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I can find a substring with using strstr function. For example I can find "Hello" substring, but I want to find "Hello" and "welcome". Not only one of them I want to find both of them. I want to think about "hello" and "welcome" like they are the same word. If the program can find the world "hello" it returns false, if the program can find the world "welcome" it returns false but if the program can find the words "hello" and "welcome" it returns true. how can I do that? 

int main(){

int total=0;
char *p="Hello world welcome!";
   while ( strstr(p,"Hello") != NULL ) {
      printf("%s", p); // to know the content of p
      p++;
      total++;
   }
 printf("%i", total);
 getch(); // pause
}
user3648443
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    How was putting the `strstr` inside a `while` loop supposed to help you? It will find the substring on the first attempt or it will not. No further action is needed. – Jongware Oct 19 '14 at 11:46
  • @Jongware I concur. The only thing more unusual than the while-looped `strstr` is that it seems to be rearing up in the posted answers as well. I suppose we could *both* be in the land of the clueless, but I'm sorta doubting it right now. – WhozCraig Oct 19 '14 at 12:07
  • Right. As it is, the loop increases the number of occurrences for every *character* that the search string is beyond the start. For `welcome`, for example, it would return 12. – Jongware Oct 19 '14 at 12:10

3 Answers3

2
#include <stdio.h>
#include <string.h>

char find_two(char* p, const char* first, const char* sec) {
    char* t1 = strstr(p, first);
    char* t2 = strstr(p, sec);
    if (t1 != NULL && t2 != NULL) {
        return 1;
    }
    else {
        return 0;
    }
}

int main(void)
{
    char* p = "hello world welcome";
    printf("%d\n", find_two(p, "hello", "welcome"));
    printf("%d\n", find_two("hello i am xx", "hello", "welcome"));
    printf("%d\n", find_two("welcome i am xx", "hello", "welcome"));
    printf("%d\n", find_two("testing abc", "hello", "welcome"));

    return 0;
}

output:

1
0
0
0

EDIT:

Some different implementation of find_two (as suggested by @Jongware) :

char find_two(char* p, const char* first, const char* sec) {
    char *t1, *t2;
    if ((t1 = strstr(p, first)) == NULL) {
        return 0;
    }
    if ((t2 = strstr(p, sec)) == NULL) {
        return 0;
    }
    return 1;
}
macfij
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0

You are a bit unclear about the problem description. What is the realtionhseip between hte two substrings? Are they connected? like "Hello welcome"? Even though your codes lets one conclude that you want to count occurences this is not explicitly stated in your question. In general you can use the strstr function as often as you want. Two count two strings - why should you not do:

int total_hello=0;
int total_welcome=0;
char *p="Hello world welcome!";
char *p_1=p;
char *p_2=p;
while ( strstr(p_1,"Hello") != NULL ) {
   printf("%s", p_1); // to know the content of p
   p_1++;
   total_hello++;
}
while ( strstr(p_2,"welcome") != NULL) {
    printf("%s", p_2);
    p_2++;
    total_welcome++;
}
return total_hello > 0 && total_welcome>0;

to count hellos and welomces?

Note that i have created copies of the original "char* p" variable and feed that as a parameter into the strstr function.

Matthias
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  • I want to think about "hello" and "welcome" like they are the same word. If the program can find the world "hello" it returns false, if the program can find the world "welcome" it returns false but if the program can find the words "hello" and "welcome" it returns true. – user3648443 Oct 19 '14 at 11:55
  • I see. Please re-phrase your question to point that out more explicitly in order to ease understanding for future readers. – Matthias Oct 19 '14 at 11:58
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int main(){
    char *p="Hello world welcome!";
    printf("%i", strstr(p, "Hello") && strstr(p, "welcome"));
    return 0;
}
BLUEPIXY
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