Read multiple scanf numbers separated by space

Question

I need to make a program that receives a number of elements from a vector, and then each element of that vector, but in the same scanf with spaces. Only I don’t know how to do this, someone can help me.

Example:

3
1 2 3

Answer 1

If you want to read several separate numbers of space, then you want to read it all as one string and basically make split on a certain separator, in this case the space. The easiest and native way to do this is to use strtok. This function reads a part of a string until it picks up the specified tab, and then from the last point it is possible to call again to pick up another bit.

Example:

int quant;
scanf("%d", &quant);
int vetor[quant];
char nums[512]; //espaço para os numeros todos como um texto
scanf(" %[^\n]", nums); //lê todos os números como um texto
char *token = strtok (nums," "); //lê até ao primeiro espaço para a variavel token
int pos = 0; //posição para guardar os numeros no vetor começa em 0

while (token != NULL && pos < quant) {
    vetor[pos++] = atoi(token); //guarda o valor convertido em numero no vetor e avança
    token = strtok (NULL, " "); //lê até ao próximo espaço a partir de onde terminou
}

Conversion of text to number was done with atoi. It’s important to note that the rest strtok not the first, they take as the first parameter NULL to indicate that they are sequels to the previous.

Now just use the number array:

int i;
for (i = 0; i < tamanho; ++i){
    printf("%d\n", vetor[i]);
}

That gives you the following exit:

1
2
3

See code working on Ideone

Answer 2

If I understand correctly you are trying to read numbers and insert in a vector, being that these trying to make this reading with more than one number... Follow the example:

#include<stdio.h>
#include<stdlib.h>
#define N 3
 int main()
 {
 int i,x;
 int v[N];
 scanf("%d %d",&i,&x);
 v[0]=i;
 v[1]=x;
 v[2]=0;

 } 

This is a small example... scanf("%d %d",&x,&i);
Follows the always % criteria with the type of variable in case d or i of decimal or integer (%d) repeats more than once if it is more than one variable and then uses the &.

Answer 3

I couldn’t find a way to pass a vector or a pointer to a vector, to a scanf. See if this way helps you:

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

void pegaVetor(int* vetor, int qtd)
{
    int i;

    fflush(stdin);
    printf("Entre o vetor, abaixo:\n");
    for (i = 0; i < qtd; ++i)
    {
        scanf("%d", &vetor[i]);
    }
}

double media(int* vetor, int qtd)
{
    int i;
    int soma = 0;

    for (i = 0; i < qtd; ++i)
    {
        soma += vetor[i];
    }

    return (double)soma / qtd;
}

int main()
{
    int* vetor;
    int n;

    do
    {
        fflush(stdin);
        printf("Digite o numero de elementos (0 para sair): ");
        scanf("%d", &n);
        if (n)
        {
            vetor = (int*)malloc(n * sizeof(int));
            pegaVetor(vetor, n);
            printf("A media aritmetica do vetor e: %f\n", media(vetor, n));
            free(vetor);
        }
    } while (n);

    return 0;
}

Possible input token delimiters, for the scanf, are blanks and/or Enters.