使用scanf进行错误检查

Question

对于我的任务，用户输入1到9之间的5个整数来表示5个9面的骰子卷，然后用它们计算得分。我们还需要能够检测和无效输入，即1-9之间的5个整数以外的任何内容。问题是，当我为我的任务运行自动测试时，当输入少于5件事情时，出现运行时错误。

我的错误校验码（忽略countArray的事情，在程序是为以后）：

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

#define TRUE 1 
#define FALSE 0 

#define ARRAY_SIZE 5 

... 

int main(void) { 

    int numbers[ARRAY_SIZE]; 
    int scanFail = 0; 

    int i = 0; 

     ... 

     // Check for if 5 integers between 1 and 9 have been entered 

    while (i < ARRAY_SIZE && scanFail == FALSE) { 

     if (scanf("%d", &numbers[i]) != 1) { 
      scanFail = TRUE; 
     } 

     if (numbers[i] < 1 || numbers[i] > 9) { 
      scanFail = TRUE; 
     } 

     countArray[i] = ARRAY_NOT_COUNTED; 
     i++; 

    } 

    if (scanFail == TRUE) { 
     printf("Invalid Input: 5 integers 1..9 must be supplied.\n"); 
     return EXIT_FAILURE; 
    } 

    ... 

这是自动测试说：

Test10 (1 2 3) - failed (errors) 

    Your program produced these errors: 

    Runtime error: uninitialized variable accessed. 

    Execution stopped here in main() in youChew.c at line 65: 

    \t\t} 
    \t\t 
    -->\t\t if (numbers[i] < 1 || numbers[i] > 9) { 
    \t\t scanFail = TRUE; 
    \t\t} 

    Values when execution stopped: 

    i = 3 
    numbers = {1, 2, 3, 69513217, -22336628} 
    scanFail = 1 
    numbers[i] = 69513217 

    Test 11 (potato) - failed (errors) 

    Your program produced these errors: 

    Runtime error: uninitialized variable accessed. 

    Execution stopped here in main() in youChew.c at line 65: 

    \t\t} 
    \t\t 
    -->\t\t if (numbers[i] < 1 || numbers[i] > 9) { 
    \t\t scanFail = TRUE; 
    \t\t} 

    Values when execution stopped: 

    i = 0 
    numbers = {69515968, 0, 8192, 69513217, -18240628} 
    scanFail = 1 
    numbers[i] = 69515968 

我不是真的确定如何解决它，所以任何帮助表示赞赏。

Answer 1

恕我直言，立即断开回路通常产生比保持标志更可读的代码..

在你的情况下，问题是，如果scanf函数失败，你没有看过的数量，但要检查它是否（未初始化的值）介于1和9之间。该测试甚至不应该发生。 快速失败。