Thread: Enter n number of persons (Structs, pointers, memory allocation)

You don't allocate additional memory for the person's name. It's a miracle it runs even once!...

Either make that member a static array or call malloc for it before scanf.

This crashes too, so I guess that is not how you meant?
And what do I need to do to use a char pointer?

Wait there is a fast way to enter n persons without malloc and
using an array of for example 100 elements?

Code:

    
    int amountOfPersons;
    printf("Enter number of persons to add: ");
    
    // Calculate storage for n amount persons
    struct Person* person = (struct Person*)malloc(sizeof(struct Person) * amountOfPersons);
    scanf("%d", &amountOfPersons);
    
    addPerson(person, amountOfPersons);
    printPersons(person, amountOfPersons);
    
    free(person);

Nonono, I meant inside your addPerson() function.

Originally Posted by DecoratorFawn82

This crashes too, so I guess that is not how you meant?
And what do I need to do to use a char pointer?

Wait there is a fast way to enter n persons without malloc and
using an array of for example 100 elements?

ok you asked, so I show. Also shows two ways for this char thing 1. char *pointer, and 2. char var[50]; just need to look to see it. I am kind of reluctant to post everything GReaper was helping you, but this is just not complete if I remove some of it. I know, I'll just pull a "Oh well"

Code:

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

// to get inout off command line and 
//put it into a struct array
//fprintf to file.
//then read and print back file

typedef struct Accounts
{
    char fristName[50];
    char *lastName;
    int IDNumber;
    float decimal_point_number;
}account;


int main (int argc, const char **argv)
{
    if (argc < 2)
    {
        printf("no outfile specified\n");
        return -1;
    }
    FILE *outfile;
    
    if ( (outfile = fopen(argv[1], "w+")) == NULL )
    {
        printf("File < %s > Not Able to be Opened\n", argv[1]);
        return -1;
    }
    
    char buffer[1024];
    char Fname[50], Lname[50];
    int id = 0;
    float dpn = 0.0;
    int newRecords = 0, i = 0;
    
    printf("Amount of new records needed?\n");
    scanf(" %d", &newRecords);
    
    account newAccounts[newRecords];
    
    memset(newAccounts, 0, newRecords * sizeof(account));
    
    while (  i < newRecords)
    {
        printf("Add Frist name Last Name Id, decimal point number\n");
        getchar(); 
        
        fgets(buffer, sizeof buffer, stdin);
        sscanf(buffer, "%s%s%d%f", Fname,Lname,&id,&dpn);
        
        // The part where you do that special thing to get char's to work 
       // removed intentionally. 
      // now the rest of the stuff
      
        newAccounts[i].IDNumber = id;
        newAccounts[i].decimal_point_number = dpn;
        i++;    
        printf("\n\nRecord %d gotten\n"
        "%d Left to go \n",i, ( newRecords - i));
    }
    
    for (size_t a = 0; a < sizeof(newAccounts)/sizeof(newAccounts[0]); a++)
        fprintf(outfile, "Name %s %s ID %d some Decimal Number %.2f\n", newAccounts[a].fristName,
        newAccounts[a].lastName,newAccounts[a].IDNumber,newAccounts[a].decimal_point_number);
        
    for (size_t a = 0; a < sizeof(newAccounts)/sizeof(newAccounts[0]); a++)
        printf("Name %s %s ID %d some Decimal Number %.2f\n", newAccounts[a].fristName,
        newAccounts[a].lastName,newAccounts[a].IDNumber,newAccounts[a].decimal_point_number);
    
    
    fclose(outfile);
    
return 0;    
}

use it how ever you want.