将数组传递给函数时的异常行为

Question

#include <stdio.h>
#define SIZE 5

void func(int*);
int main(void)
{
  int i, arr[SIZE];
  for(i=0; i<SIZE; i++)
    {
          printf("Enter the element arr[%d]: ", i);
          scanf("%d", &arr[i]);
        }//End of for loop

  func(arr);
  printf("The modified array is : ");

  for(i=0; i<SIZE; i++)
    printf("%d ", arr[i]);

  return 0;

}

  void func(int a[])
 {
   int i;

   for(i=0; i<SIZE; i++)
    a[i] = a[i]*a[i];
 }

输出:::

当我输入整数元素时输出是OK.但是当我输入一个像1.5这样的浮点值时,它没有要求其他元素,而O/P如图所示.我认为它应该隐式地将类型转换为1.5 1但它没有发生..你能告诉我为什么会这样吗？有关编译器的所有信息如图所示.

Answer 1

当您扫描scanf("%d")的值1.5将停在小数点并返回1时.

在接下来的调用时scanf,指针将仍然指向小数点,因为没有数字有扫描您的扫描将立即返回.

您应该检查返回值scanf- 它为您提供成功扫描的项目数,最初为1小数点前1 ,从0 开始为0.

顺便说一句,scanf代表"扫描格式化",我保证你找不到比用户输入更多未格式化的内容.

调查寻找fgets线路输入.这是我经常用于此目的的函数的副本:

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

#define OK       0
#define NO_INPUT 1
#define TOO_LONG 2
static int getLine (char *prmpt, char *buff, size_t sz) {
    int ch, extra;

    // Get line with buffer overrun protection.
    if (prmpt != NULL) {
        printf ("%s", prmpt);
        fflush (stdout);
    }
    if (fgets (buff, sz, stdin) == NULL)
        return NO_INPUT;

    // If it was too long, there'll be no newline. In that case, we flush
    // to end of line so that excess doesn't affect the next call.
    if (buff[strlen(buff)-1] != '\n') {
        extra = 0;
        while (((ch = getchar()) != '\n') && (ch != EOF))
            extra = 1;
        return (extra == 1) ? TOO_LONG : OK;
    }

    // Otherwise remove newline and give string back to caller.
    buff[strlen(buff)-1] = '\0';
    return OK;
}

 

// Test program for getLine().

int main (void) {
    int rc;
    char buff[10];

    rc = getLine ("Enter string> ", buff, sizeof(buff));
    if (rc == NO_INPUT) {
        // Extra NL since my system doesn't output that on EOF.
        printf ("\nNo input\n");
        return 1;
    }

    if (rc == TOO_LONG) {
        printf ("Input too long [%s]\n", buff);
        return 1;
    }

    printf ("OK [%s]\n", buff);

    return 0;
}

一旦你开始使用该功能,你可以sscanf根据自己的内容,更轻松地处理错误.