而在C中使用EOF时

Question

I'm trying to read the data from a txt file with the following code but it's print only the first line from file.

int main() {
    int chave;
    char ordem[5];
    struct tTree *arvore = (struct tTree*)malloc(sizeof(struct tTree));
    arvore->raiz = NULL;
    scanf("%s", ordem); 
    printf("%s\n", ordem);
    setbuf(stdin, NULL);  
    do {
        scanf("%d", &chave);
        insere(criaItem(chave), arvore);
        setbuf(stdin, NULL); 
    } while(chave != EOF);

    if(strcmp(ordem, "PRE") == 0) {
        pre(arvore->raiz);
    }
    else if(strcmp(ordem, "POS") == 0){
        pos(arvore->raiz);
    }
    else if(strcmp(ordem, "IN") == 0){
        in(arvore->raiz);
    }
    printf("%d\n", altura(arvore->raiz)-1);
    system("pause");   
}

Answer 1

while (scanf("%d", &chave) == 1)
{
    insere(criaItem(chave), arvore);
    printf("Read: %d\n", chave);  // Debugging
    // setbuf(stdin, NULL);  // Pointless once there's been an I/O operation on stdin
}

This tests for EOF and other errors correctly, with the test up front. Almost always, it is best to do the read operation and test that it succeeded at the start of the loop.

There were a large number of problems with what you'd written, not least of which was that typing -1 as an input value would have terminated your loop.

Answer 2

scanf() will return EOF, but not put it into chave . Shouldn't your code look something more like this?

int ret;
do {
    ret = scanf("%d", &chave);
    if ( ret == 1) {
        insere(criaItem(chave), arvore);
        setbuf(stdin, NULL); 
    }
} while( ret != EOF);