pointer in for loop

[crumbs12]

hello friends,
I am having a problem.

This code works just fine when I print as soon as I assign the string to
the pointer.

Code:

ptr->main = malloc(sizeof(detail)*(660)+1);
strcpy(ptr->main[count].key,token[i]);
printf("key key %d %s ",count, ptr->main[count].key);But when I try to do this....

      for(i=0; i < count; i++)
   {
          printf("%d %s %s \n", i,ptr->main[count].key);
      }It doesnt work.
What am I doing wrong in the for loop...
 
 

typedef structn ARRAY1{
        char time[ARRAY_SIZE];
        char date[ARRAY_SIZE];
}ARRAY1,ARR2;
 
typedef struct first{
      char name[10];
       ARRAY1 *main;
   }first;
 
typedef struct second{
      char db[10];
        ARRAY2 *other;
    }second;
in main{
  FILE *data_txt,
        struct ARRAY1 *str_ptr;   
        struct ARR2 *new_ptr;
      str_ptr = &ARRAY1_info;
      new_ptr = &ARR2_info;
 
       struct first *ptr;
       struct second *new;
 
     data_txt = fopen("data.txt","r");
 
 while (fgets(line,100,data_txt)!=NULL)
 {
 
 
 
trim(line);
 strcpy(first_info.name,"ccmlmd");
        if ((strlen(line) > 1)&&(read!=0)){
        lcount++;
        tokens = split(line, delim);
        for(i = 0; tokens[i] != NULL; i++) {
        if (i==0){
        if (tokens[i]!=NULL){
ptr->main = malloc(sizeof(detail)*(660)+1);
        strcpy(ptr->main[count].key,token[i]);
      printf("key key %d %s ",count, ptr->main[count].key);
       }
      }
 
   }
  for(i = 0; tokens[i] != NULL; i++)
  free(tokens[i]);
  free(tokens);
  count++;
  lcount++;
      }
 
// This doesnt work
      for(i=0; i < count; i++) {
 printf("%d %s %s", i,ptr->main[i].time, ptr->main[i].date);
      }
 

[debasisdas]

Question moved to C / C++ Forum.

[boxfish]

In what way does it not work? If it gives you compiler errors, please post them here. If it gives you the wrong output, please post it here, along with the expected output. This will make it much easier for people to help you. Thanks.

[crumbs12]

Basically this doesnt print anything

 for(i=0; i < count; i++) { 
 printf("%d %s %s", i,ptr->main[i].time, ptr->main[i].date); 
      }
 

[RedSon]

Have you tried debugging it? What does printf return to you?

[crumbs12]

The printf in the for loop prints only this

 
1   
2   
 
 

But when further up in the code prints just fine.

ptr->main = malloc(sizeof(detail)*(660)+1); 
        strcpy(ptr->main[count].key,token[i]); 
      printf("key key %d %s ",count, ptr->main[count].key);
 

This prints just fine.

Only problem is that this part of the code doesnt work

      for(i=0; i < count; i++) { 
 printf("%d %s %s", i,ptr->main[i].time, ptr->main[i].date); 
      } 
 

[RedSon]

what type of data is ptr->main[i].time and ptr->main[i].date?

[crumbs12]

As I posted above

typedef structn ARRAY1{ 
        char time[ARRAY_SIZE]; 
        char date[ARRAY_SIZE]; 
}ARRAY1,ARR2; 
 
typedef struct first{ 
      char name[10]; 
       ARRAY1 *main; 
   }first; 
 
typedef struct second{ 
      char db[10]; 
        ARRAY2 *other; 
    }second; 
 

Thats the info I am trying to catch

[boxfish]

It's hard for me to tell what's wrong with your program because the code you posted has typos and does not compile. Two problems I can see are that in your posted code, you have not initialized ptr->main[i].time or ptr->main[i].date, and the line you posted separately,

printf("%d %s %s \n", i,ptr->main[count].key);

has one too many %s, but I don't know if these things are causing problems for you.

[crumbs12]

Oh ok...But since I have already initialized the pointer further up...wouldnt that be enough...or do I have to initialize the ptr again in this part of the code...?

  for(i=0; i < count; i++) {  
 printf("%d %s %s", i,ptr->main[i].time, ptr->main[i].date);  
      } 
 

[boxfish]

You do not initialize the date or time members in your code. You do initialize

ptr->main[count].key

but the ARRAY1 struct does not have a member called key. I'm afraid the code you posted does not make any sense.

[crumbs12]

I am sorry, please subsitite the 'key' and 'value' fields with 'time' and 'date'.

[RedSon]

Instead of making us substitute everything and try to force your code to work, why don't you provide a listing of your code that compiles so we can see what you are doing.

[crumbs12]

OK here is the corrected code.

typedef structn ARRAY1{
        char time[ARRAY_SIZE];
        char date[ARRAY_SIZE];
}ARRAY1,ARR2;
 
typedef struct first{
      char name[10];
       ARRAY1 *main;
   }first;
 
typedef struct second{
      char db[10];
        ARRAY2 *other;
    }second;
in main{
  FILE *data_txt,
        struct ARRAY1 *str_ptr;   
        struct ARR2 *new_ptr;
      str_ptr = &ARRAY1_info;
      new_ptr = &ARR2_info;
 
       struct first *ptr;
       struct second *new;
 
     data_txt = fopen("data.txt","r");
 
 while (fgets(line,100,data_txt)!=NULL)
 {
 
 
 
trim(line);
 strcpy(first_info.name,"ccmlmd");
        if ((strlen(line) > 1)&&(read!=0)){
        lcount++;
        tokens = split(line, delim);
        for(i = 0; tokens[i] != NULL; i++) {
        if (i==0){
        if (tokens[i]!=NULL){
ptr->main = malloc(sizeof(detail)*(660)+1);
        strcpy(ptr->main[count].time,token[i]);
      printf("time time %d %s ",count, ptr->main[count].time);
       }
      }
 
   }
  for(i = 0; tokens[i] != NULL; i++)
  free(tokens[i]);
  free(tokens);
  count++;
  lcount++;
      }
 
// This doesnt work
      for(i=0; i < count; i++) {
 printf("%d %s ", i,ptr->main[i].time);
      }
 

[newb16]

@crumbs12
If it doesn't print anything, what is value of 'count'?

[donbock]

The code in post #14 is incomplete and contains typos ...

Line 1: "struct", not "structn".
Lines 2 and 3: ARRAY_SIZE is undefined.
Line 16: "int", not "in".
Line 17: this implies that you included <stdio.h>.
Lines 20 and 21: ARRAY1_info and ARR2_info are undefined.
Line 26: you don't check if fopen fails.
Line 28: "line" is undefined.
Line 33: function "trim" is undefined.
Line 34: this implies that you included <string.h>.
Line 34: "first_info" is undefined.
Line 35: "read" is undefined and uninitialized.
Line 36: "lcount" is undefined and uninitialized.
Line 37: "tokens" is undefined.
Line 37: function "split" is undefined.
Line 37: "delim" is undefined and uninitialized.
Line 38: "i" is undefined.
Line 41: "ptr" is uninitialized.
Line 41: "detail" is undefined.
Line 41: this implies that you included <stdlib.h>.
Line 41: you don't check if malloc fails.
Line 42: "count" is undefined and uninitialized.
Line 42: "tokens", not "token" ... I think.
Lines 49 and 50: you didn't malloc either of these, but you're freeing them. I suppose trim() must have malloc'd them.
Line 57: ptr->main was malloc'd at line 41, are you sure it wasn't also free'd by lines 49 or 50?


These aren't errors, but could be cause for confusion:

Lines 1 and 4; 6 and 9; 11 and 14: the struct name is the same as the typedef name. Some people prefer to do it like this, others prefer to avoid all ambiguity.
Line 8: "main" is typically pseudo-reserved for the name of the main function.
Lines 18, 19, 23, and 24: after going to the trouble of using typedefs you ended up using the structure declarations.

These comments are based on code inspection. Additional problems might come to light if I tried to compile the code.

[RedSon]

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