Sequence reading of numbers separated by space

You can use scanf() , because with it you can distinguish the numbers from each other.

To solve your problem, one possible way is to read one number at a time and at each reading, dynamically allocate enough memory to read that number, using malloc() . For this you would need a structure that expands its size dynamically. This avoids the problem of:

A data structure that assists you in this is a linked list . An alternative can be a dynamic array.

Either way you need to define an end identifier. Some character that will dictate when the sequence ends. If it is a sequence of integers, you can use a negative character to indicate the end of the sequence. For example, -1 . Or EOF .

But , the following reflection might fit here: Is it necessary for all numbers to be in memory at once?

A very simple example to illustrate this scenario is a accumulator .

Scenario: Imagine that a program is requested to add up all the numbers that the user types. Solution: One approach is to save all of them in memory and then iterate in them, adding them up. A simpler approach would be to just make an accumulator:

soma = soma + numero_da_entrada;

I hope I have helped!

Issue 1 : Apparently, you can use% return of% to know when there are no more numbers to read:

int numero;
while(scanf("%d", &numero) == 1) { // scanf retorna 1 quando a leitura for bem sucedida
    printf("%d", numero);
}

Issue 2 : To read the entire line and stop when you press enter:

int numero;
char proxChar;
while(scanf("%d%c", &numero, &proxChar) == 2) { 
        printf("%d", numero);
        if(proxChar == '\n') break; 
}

Read only one number at a time. The result of scanf will then be 1 if the reading was successful, or zero if it failed, and in this case the line was read through.

For each number read, allocate space dynamically with malloc. Use a linked list to store the read numbers.

You can use fgets to pick up the entry and strtok to break into parts:

char entrada[100];   // Para obter até 100 caracteres da entrada
int * elementos[10]; // Array com capacidade para 10 elementos
int i = 0;

int tamanhoArray = sizeof elementos / sizeof(int);

if(fgets(entrada, sizeof entrada, stdin) != NULL) {
    for (char *pedaco = strtok(entrada, " "); pedaco != NULL; pedaco = strtok(NULL, " ")) {

        // Se atingir a capacidade do array
        if (i >= tamanhoArray) {
            puts("Não foi possível adicionar mais itens na lista!");
            break;
        }
        elementos[i++] = pedaco;
    }

    for (int n = 0; n < tamanhoArray; ++n) {    
        printf("Indice [%d] = %s\n", n, elementos[n]);
    }
} 

See DEMO

If you prefer to create array with size based on the number of spaces:

char entrada[100];  // Para obter até 100 caracteres da entrada
int qtdEspacos = 1;
int i = 0;

if(fgets(entrada, sizeof entrada, stdin) != NULL) {
    char *ptr = entrada;

    while((ptr = strchr(ptr, ' ')) != NULL) { // Se encontrou espaço
        qtdEspacos++;
        ptr++;
    }

    // Cria o array com tamanho baseado na quantidade de espaços na string
    int * elementos[qtdEspacos];

    for (char *pedaco = strtok(entrada, " "); pedaco != NULL; pedaco = strtok(NULL, " ")) {
        elementos[i++] = pedaco;
    }

    for (int n = 0; n < qtdEspacos; ++n) {    
        printf("Indice [%d] = %s\n", n, elementos[n]);
    }
}

See DEMO