Thread: reading the content of a file into an array of struct

i am writing a function that reads the content of the file into a dynamically-allocated array of "Point" struct.

Code:

#include <stdio.h>
#include <stdlib.h>




typedef struct{
    double x;
    double y;
}Point;

void readPoints(char* fileName, int* numPoints){
    int i;
    FILE *f = fopen(fileName, "r");


    if(f != NULL){
        fscanf(f, "%d", numPoints);    
        printf("the first line =  %d \n", *numPoints);
        
        Point *poin = (Point*)malloc((*numPoints)*sizeof(Point));


        while (!feof(f)){
            for(i=0; i<(*numPoints);i++){
                fscanf(f, "%f,%f", poin->x, poin->y);    
                printf("%f , %f\n", poin->x, poin->y);


            }
        }
        fclose(f);        
        printf("END\n");
        
        free(poin);
    }
    else{
        perror("Could not open..!\n")    ;
    }
    
    
    
}

the file will look something like this
4
2.35,6.14
5.5,7.0
0.0,-55.9
14084.1,39864

the function compiles fine,,,, but it doesnt output the correct result.. ur help will be appreciated..

Originally Posted by WaltP

Code:

fscanf(f, "%d", numPoints);   
printf("the first line =  %d \n", *numPoints);

Your parameter's * is mixed up.

Nah, looks good to me. It's passed in as an int pointer. That means no * or & when used with fscanf (already a pointer), but you need a * to dereference the int if you're going to printf it with %d.

anduril462, thank u so much,, i looked at the link u gave,,, they helped me alot,, anddd all those tip were really helpful too...

i found all of the bugs and fixed themm all... thanks again,,

Is it working now? Wouldn't you also need to index poin with "i" since it's an array of struct point? Also, in case you don't know, it is ok to use the same name for an instance of the struct as the type name, in this case you use a capital p for the type but you could do, say: struct Point *point;