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A C language problem in link list traversal

Hi guys,

I've difficulties in developing a new link list by a loop

First of all, i let the user enter people's number: Numbger

And create an empty link list

And then read data to link list by for loop.
rec *f; //by using another pointer
f=p; //f indicates to the node which p indicates to
printf("OK1\n");//for my test
for(i=0;i<=Number-1;i++){
fscanf(fp1,"%s %s %s",&(f->Firstname),&(f->Lastname),&(f->Phonenumber));
f=f->Link;
}
//在嘗試用回圈寫入number比資料入link list時發生了問題
//while I 'm using a loop to enter messages to nodes ,
//errors occur in the statement f=f->Link;
//But WHY?><"
//If i can'g use a loop , then what should i do ?
printf("OK2\n");

printf("%s\n",f->Firstname);
printf("%s\n",f->Lastname);
printf("%s\n",f->Phonenumber);
printf("%s\n",f->Link->Firstname);
printf("%s\n",f->Link->Lastname);
printf("%s\n",f->Link->Phonenumber);//for testing the date be written or not?

printf("OK3\n");

Thank you for your help >(_ _)<

Re: A C language problem in link list traversal

typedef struct people{
char Firstname[10];
char Lastname[10];
char Phonenumber[10];
int Seq_num;
//the larger number in Seq_num stands for the smaller number in value.
struct people *Link;
} rec;

Re: A C language problem in link list traversal

Code:

#include <stdio.h>

#include <stdlib.h>



FILE *fp1;

int main()

{

typedef struct people{

char Firstname[10];

char Lastname[10];

char Phonenumber[10];

int  Seq_num;



struct people *Link;

} rec;





int Number;

int count;

int i;

rec *p;



printf("Please enter the source of the first matrix\n");



scanf("%s",matrix1_name);



fp1=fopen(matrix1_name,"r");

if(fp1==NULL)

printf("some error has occured ,but don't worry and you'll work it out");

else

printf("writing\n");

  

printf("Please tell me how much people's information in the file? \n");

scanf("%d", &Number);

  



p=(rec *)malloc(Number*sizeof(rec));//根據link01.c example知 ()內就是P的宣告



  







rec *f;

f=p;





printf("OK1\n");

for(i=0;i<=Number-1;i++){

fscanf(fp1,"%s %s %s",&(f->Firstname),&(f->Lastname),&(f->Phonenumber));

f=f->Link;

}



printf("OK2\n");



printf("%s\n",f->Firstname);

printf("%s\n",f->Lastname);

printf("%s\n",f->Phonenumber);

printf("%s\n",f->Link->Firstname);

printf("%s\n",f->Link->Lastname);

printf("%s\n",f->Link->Phonenumber);





printf("OK3\n");

/*while(f->Link!=NULL){

fscanf(fp1,"%s",&(f->Firstname));

fscanf(fp1,"%s",&(f->Lastname));

fscanf(fp1,"%s",&(f->Phonenumber));



}







printf("%s",f->Firstname);



/*count=0;

while(count!=Number-1){

f=f->Link;

count++;

}

f->Link=NULL;









fclose(fp1);

return 0;

}

Re: A C language problem in link list traversal

You haven't set p to point to memory that contains the rec structures in which to place the values.