问分段故障11，使用指针并返回它们

EN

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

typedef struct
{   
    float xcord;
    float ycord; 
}POINTS;

int readPoints(char* file, int numofpoints);
int calc(POINTS* points, int numofpoints);

int main(int argc, char* argv[])
{   

int numoffiles;
FILE* file; 
int result, i;
numoffiles = argc;

POINTS* pointer;
int numofpoints;

if(numoffiles == 1)
{   
    printf("Please enter a file\n");
}

for(i=1; i<numoffiles; i++)
{   
    file = fopen(argv[i], "r");
    fscanf(file, "%d", &numofpoints);
    pointer = readPoints(file, numofpoints);

    if( pointer == NULL)
    {   
        printf("Error return from readPoints function");
    }


    result = calc(&pointer[i], numoffiles);


    printf("%12f", result);
    free(pointer);
}
}

int readPoints(char* file,int numofpoints)
{
    int i, j;

    POINTS* Pointstructs;
    Pointstructs = (POINTS*)malloc((numofpoints)*sizeof(POINTS));

    if(file == NULL)
    {
        printf("Error transferring file into readPoints\n");
    }

    for(i=0; i<numofpoints; i++)
    {
        fscanf(*file, "%f, %f", &Pointstructs[i].xcord, &Pointstructs[i].ycord);
        printf("%f, %f", Pointstructs[i].xcord, Pointstructs[i].ycord);
    }

    return Pointstructs;
}

int calc(POINTS* points, int numofpoints)
{
    int i=0, j=0;
    int answer;

    while(i<numofpoints && j<numofpoints)
    {
        answer += points[i].xcord * points[j].ycord;
        i++;
        j++;
    }    
return answer;
}