Thread: search function failure

Hi there.

I have problems with my search function when i read in the command search and then also read in the word that needs to be searched. eg when i enter the command "search blah" it it supposed to search for the word "blah" through the file and then print out the lines which matches the search phrase. Between the search command and the phrase there is a whitespace. Im trying to separate the string so that only the uses the last bit of the search command becuase since i dont want it to also compare it to the "search" when i type it in.

However it is not working.

Can some1 plz tell me wats going on and tell me how to fix this.

Thanks in advance.

Code:

int search(char str[][100],char input[],int filelines);

int main(int argc,char*argv[]){
  
  FILE *fp;
  
  int filelines=0;
  
   int i=0;
       
   char str[1000][100];

   char input[100];
   

  while(!EXIT_SUCCESS){     

     i=0;
      
     printf("Enter command > ");
            
     fgets(input,100,stdin);
       
        if(strcmp(input,"print\n") == 0){

                 fp=fopen(argv[1],"r");
 / /i have loop here to read in the contents of file.
 
         }
 
        search(str,input,filelines);
 
  }
                 
return 0;

}

int search(char str[][100],char input[100],int filelines){

    char input2[100];

    int j=0;

    int i=0;

   // char *strptr;

    char *strptr = &str[0][100]; // this array is where the stuff is when the file was read in in the main function
  
    j=strlen(input2);

    input2[j-1]='\0';

    if(strcmp(input,"search ") == 0){
   
       fgets(input2,100,stdin);

       while((strptr = strstr(strptr,input2)) != NULL){//compares to the stuff in the array where the contents of the file are.
            
            printf(" %s",str[i]);

            i++;            
             
            strptr++;

       }

     }

return 0;

}

fgets reads a line up to a \n or until N elements. If you want that line split into words, use sscanf to split it up.


Quzah.

It doesn't have to. Read the man page. Besides, you can always just peel off the first word and then treat everything else as the remainder line.


Quzah.

There are lots of ways to do it. You can use a loop and copy characters one at a time to some place else until you hit a space, then copy everything else some place else. You can use a couple of format specifiers and just use sscanf. There are lots of ways to do it. So how about actually trying?


Quzah.

Code:

abcdefg abcdefg abcdefg
0123456^

You loop until you hit a space.
Then you need to add a \0 to the array you've copied the word to, so that it makes it an actual string.
Then you increment your counter to skip that space, and you continue copying until you have copied the \0 to your second string.


Quzah.

I think strtok is maybe a good thing to use here.

Code:

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

void for_example (char *string) {
	char *tok = strtok(string," ");
	while (tok) {
		printf("->%s<-\n", tok);
		tok = strtok(NULL," ");
	}
}


int main(int argc, const char *argv[]) {
	char input[4096] = {0};
	int i;

	if (argc < 2) {
		puts("No arg!");
		return -1;
	}

	for (i=1;i<argc;i++) {
		strcat(input,argv[i]);
		input[strlen(input)] = ' ';
	}

	for_example(input);

	return 0;
}

You can compile this and then run it from the command line adding whatever string you are want to deal with, eg:

[root/media/sda6/root/C] ./a.out search and this
->search<-
->and<-
->this<-


I would copy the items into an array of strings and then use those line by line when searching the file -- than is, search each line once for each term rather than read the file once for each term. Your existing code is a little odd, lemme post that separately.

Code:

int search(char str[][100],char input[100],int filelines){

It's not necessary to use "char input[100]", use "char *input". It's the same anyway (you cannot pass the value of a whole array, you can just pass a pointer).

Code:

    char input2[100];
    char input3[100];
    int j=0;
    int i=0;
    int k;
  
    char *strptr = input3;
   
    j=strlen(input)-1;
    input[j]='\0';

Why do you do this?

Code:

    for(i=0; input[i] != ' '; i++){
       input[i]=input2[i];

These are backward.

Code:

   
    while(input[j] != ' '){
         j--;
         k=j;
    }

    while(input[k]!='\0'){
         input[k]=input3[k];

Backward again! Also this whole section is very torturous...why do you want to work thru the string from both ends?

Code:

 
    if((strcmp(input2,"search")) == 0){
       while((strptr = strstr(strptr,input3)) != NULL){
            printf("%s",str[i]);

I don't understand the purpose of str[][] so am lost at this point -- are those the lines from the file?

Okay, this is what I meant earlier. It's a development of the function from the last post:

Code:

void for_example (char *string) {
	char *tok = strtok(string," "),
		array[10][32], buffer[1024];
	int c = 0, i;
	FILE *in = fopen("test.c","r");

/* populate "array" */
	while (tok) {
		printf("->%s<-\n", tok);
		if (strcmp(tok,"search") == 0) {
			tok = strtok(NULL," ");
			continue;
		}
		strcpy(array[c++],tok);
		if (c==10) break;	// max terms
		tok = strtok(NULL," ");
	}

/* scan file */
	while (fgets(buffer,1024,in)) {
		for (i=0; i<c ;i++) {
			if (strstr(buffer,array[i])) {
				printf("%s",buffer);
				break;	// don't reprint lines
			}
		}
	}
	fclose(in);
}

"test.c" is the source code itself, and the rest is the same as before. So when I run this:

./a.out search str tok arg

I get:

Code:

->search<-
->str<-
->tok<-
->arg<-
#include <string.h>
void for_example (char *string) {
	char *tok = strtok(string," "),
	while (tok) {
		printf("->%s<-\n", tok);
		if (strcmp(tok,"search") == 0) {
			tok = strtok(NULL," ");
		strcpy(array[c++],tok);
		tok = strtok(NULL," ");
			if (strstr(buffer,array[i])) {
int main(int argc, const char *argv[]) {
	if (argc < 2) {
		puts("No arg!");
	for (i=1;i<argc;i++) {
		strcat(input,argv[i]);
		input[strlen(input)] = ' ';

Only the lines with "str", "tok", or "arg" in them The only problem with this is you can't search for "search".

It doesn't really matter what it's guaranteed to be, since he's just comparing to a constant--his loop condition never changes.


Quzah.