将结构数组传递给C中的值函数

Question

I want to pass an array of three structures to a function that sorts the three numbers stored in the array of structures, but do not want to change the actual values ​​, as arrays are passed by reference , there's my problem , any ideas accept thanks :)

Here is my code for review:

#include <stdio.h>
#define N 3
typedef struct
{
    int digito;
} numbers;

void  sort(numbers tabla[], int nro);
void enternums(numbers  tabla[], int nro);

int main()
{
    static numbers enter[N];
    int i, j, tmp;
    enternums(enter, N);
    printf("Data before entering the function...\n\n");
    for (i = 0 ; i < N ; i++)
    {
        printf("%d\n", enter[i].digito);
    }
    sort(enter, N);

    printf("After entering data function....\n\n");
    for (i = 0 ; i < N ; i++)
    {
        printf("%d\n", enter[i].digito);
    }
    return 0;
}

void enternums(numbers tabla[], int nro)
{
    int i;
    for (i = 0 ; i < nro ; i++)
    {
        printf("Enter a digit for the position %d:  ", i);
        scanf("%d", &tabla[i].digito);
    }
}

void sort(numbers tabla[N], int nro)
{
    int i, j, tmp;
    for (i = 1 ; i < nro ; i++)
    {
        j = i;
        tmp = tabla[i].digito;
        while ((j > 0) && (tmp < tabla[j - 1].digito))
        {
            tabla[j].digito = tabla[j - 1].digito;
            j--;
        }
        tabla[j].digito = tmp;
    }
}

Answer 1

Passing the array as a pointer ¹ to it's first element, has the advantage that you can actually pass another array to store the new values

void sort(const numbers *const tabla, numbers *resultado, int nro)
{
    int i, j, tmp;
    for (i = 1 ; i < nro ; i++)
        resultado[i].digito = tabla[i].digito;
    for (i = 1 ; i < nro ; i++)
    {
        tmp = resultado[i].digito;
        for (j = i ; (j > 0) && (tmp < resultado[j - 1].digito) ; --j)
            resultado[j].digito = resultado[j - 1].digito;
        resultado[j].digito = tmp;
    }
}

Making the while loop a for loop instead, it would make your code clearer.

And to use this

int main()
{
    static numbers enter[N];
    static numbers ordenado[N];
    int i, j, tmp;
    enternums(enter, N);
    printf("Data before entering the function...\n\n");
    for (i = 0 ; i < N ; i++)
    {
        printf("%d\n", enter[i].digito);
    }
    sort(enter, ordenado, N);

    printf("After entering data function....\n\n");
    for (i = 0 ; i < N ; i++)
    {
        printf("%d\n", ordenado[i].digito);
    }
    return 0;
}

Also, make your code safer by checking for possible errors, for example

scanf("%d", &tabla[i].digito);

should be

if (scanf("%d", &tabla[i].digito) != 1)
    Oops_there_is_a_problem_dont_use_this_value_maybe_ask_again();

---

¹ _{Which happens automatically, it's not passed by reference it's converted to a pointer} .

Answer 2

You cannot pass arrays by value unless they are contained in a struct .

You can use:

typedef struct MyStrutArray
{
   numbers  enter[N];
} MyStructArray;

and then use:

void  sort(MyStructArray array);