strstr char array inside struct array - c

Question

I have a struct defined as;
struct player {
int no, age;
char name[20];
} players[10];
Array is filled from file. What I try to do is, take input from user, add input to char array, send it to search(char lookup[]) function and strstr name field in a loop.
EDİT: Sorry I corrected the order. I'm trying to strstr in a loop.
char *p = strstr(players[x].name, inputFromUser);
but p is always null. How can I do this?
Thanks in advance.
EDIT - Code Added...
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
struct player {
int no, age;
char name[20];
} players[20];
void fillstruct(char *);
void search(char []);
int main(int argc, char *argv[])
{
int arg;
int c;
int d;
int i=0;
char a[100];
char *filename = NULL;
while((arg=getopt(argc, argv, "f:"))!=-1)
{
switch(arg)
{
case 'f':
filename = optarg;
fillstruct(filename);
break;
default:
break;
}
}
while((c=fgetc(stdin))!=EOF)
{
if(c!=10)
{
a[i]=c;
i++;
}
else
{
a[i]='\0';
search(a);
i=0;
}
}
return 0;
}
void search(char a[])
{
int i=0;
int col;
int found=0;
char *p =NULL;
while((i<20)&&(found==0))
{
p = strstr(a, players[i].name);
if(p)
{
col = p-a;
printf("\nPlayer '%s' found in '%s'.. Found index: %d", a, players[i].name, col);
found=1;
}
else
{
printf("\np=%s a=%s player[%d].name=%s", p, a, i, players[i].name);
}
i++;
}
}
void fillstruct(char *name)
{
FILE *fp;
char line[100];
int i=0;
fp = fopen(name, "r");
if(fp==NULL)
{
exit(1);
}
while(fgets(line, 100, fp)!=NULL)
{
players[i].no=i;
strcpy(players[i].name, line);
fprintf(stdout, "\nplayer=%s", players[i].name);
players[i].age=20;
i++;
}
fclose(fp);
}

Answer 1

Added as answer as suggested by mic_e
Assuming you're trying to search for a player name using the input from a user, you have the arguments of strstr in the reverse order. Also note that strstr is case sensitive.
char *p = strstr(players[x].name, inputFromUser);

Answer 2

fgets stores the \n and then stops taking input.
So suppose a player name is "user", players[i].name will be equal to "user\n" while a is "user".
So return of strstr is always NULL.
Try this instead:
p = strstr(players[i].name,a);
OR, remove the \n after taking input from file by fgets:
while(fgets(line, 100, fp)!=NULL)
{
players[i].no=i;
strcpy(players[i].name, line);
players[i].name[strlen(players[i].name)-1]='\0'; //add this line
fprintf(stdout, "\nplayer=%s", players[i].name);
players[i].age=20;
i++;
}

Answer 3

Like this:
char *p = strstr(players[x].name, inputFromUser);

Answer 4

It should work, It's fail if your input is wrong let me expalain in simple
int main()
{
char *ret;
char mystr[]="stack";
char str[]="This is stack over flow string";
ret = strstr(str, mystr);
printf("The substring is: %s\n", ret);
return(0);
}
Output is
The substring is: stack over flow string
That means
This function returns a pointer to the first occurrence in str of any of the entire sequence of characters specified in mystr, or a null pointer if the sequence is not present in str.
It case sensitive function means if try to search like
char mystr[]="Stack";//Note here first char is capital
And you got output like
The substring is: (null)
You can check your input and target string at your side by just printing content of it and verify it's correct or not.
printf("str1:%s str2:%s\n",players[x].name,inputFromUser)
char *p = strstr(players[x].name, inputFromUser);
I hope this clear your doubts.

Answer 5

That Should Work.
I think You have the problem with file reading Which fills the data array.
Please make sure that data you filled into structure is Ok.
And strstr returns address of the first Occurrence of the string1 in string2
where,
strstr(string2, string1);