segmentation fault error!

[shadow levin]

Hi every one,

I write a simple code in c,but I get segmentation fault error while running! I know it this error occurs while we want to get wrong access to a special part of memory but actually I can't find it in my code:( I attached my code in attachments ...

would you please help me?
special tanks for your help...

/*
 ============================================================================
 Name        : tamrin2.c
 Author      :
 Version     :
 Copyright   : Your copyright notice
 Description : The information of students in a university
 ============================================================================
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
 
int main() {
 
    int number;
    printf("Enter number of students :");
    scanf("%d",&number);
 
    typedef struct Student{
        char *Fname;
        char *Lname;
        char *name;
        float ave;
        int yearOfBirth;
        char *STD;
    }St;
 
    St st[number];
 
    int i;
    for(i=0;i<number;i++){
 
 
        printf("Enter %d student's first name :\n",i+1);
        scanf("%s",st[i].Fname);
        st[i].Fname=(char*)malloc(sizeof(char)*(strlen(st[i].Fname)+1));
 
 
        printf("Enter %d student's last name :\n",i+1);
        scanf("%s",st[i].Lname);
 
        st[i].Lname=(char*)malloc(sizeof(char)*(strlen(st[i].Lname)+1));
 
 
        strcpy(st[i].name,strcat(st[i].Fname,st[i].Lname));
        st[i].name=(char*)malloc(strlen(st[i].Fname)+strlen(st[i].Lname)+3);
 
        printf("Enter %d student's average : \n",i+1);
        scanf("%f",&st[i].ave);
 
        printf("Enter %d student's year of birth : \n",i+1);
        scanf("%d",&st[i].yearOfBirth);
 
        printf("Enter %d student's STD number : \n",i+1);
        scanf("%s",st[i].STD);
        st[i].STD=(char*)malloc(sizeof(char)*(strlen(st[i].STD)+1));
 
    }
 
    for(i=0;i<number;i++){
        free(st[i].STD);
        free(st[i].name);
        free(st[i].Lname);
        free(st[i].Fname);
    }
    return 0;
}

[weaknessforcats]

In yur struct Fname is a char* and you are using it in scanf. You need memory allocated before you call scanf.

The usual practice is to use a buffer of a known size in the scanf. Then you can strlen the buffer and use that to allocate for your Fname.