未找到命令，后跟段错误 11

Question

我试图制作一个可以获取类似输入的程序

   1     833N619DL  ABQ           26     204     214    1250
   1    1125N660DL  ABQ           18     211     204    1250
   1    1589N678DL  ABQ           23     206     212    1250
   2     833N659DL  ABQ           18     204     194    1250
   2    1125N656DL  ABQ           23     211     210    1250
   2    1589N665DN  ABQ           19     206     212    1250
   3     833N686DA  ABQ           23     204     204    1250
   3    1125N692DL  ABQ           27     211     216    1250
   3    1589N635DL  ABQ           26     206     210    1250
   4     833N688DL  ABQ           21     204     206    1250
   4    1125N660DL  ABQ           18     211     221    1250
   4    1589N631DL  ABQ           28     206     209    1250

此数据和输出仅输出输入中的数字(不包括数字和字母混合的列)

这是我的程序

#include <stdio.h>
#include <ctype.h>

#define MAXLINE 10000

char *itoa(int i);                  //convert integer to char array

main() {
    int temp= 0, i = 0, c, j = 0;
    char *a[MAXLINE];               //pointer array with uninitialized pointers

while((c = getchar()) != EOF)
    if(isdigit(c))
        temp = 10 * temp + c - '0';
    else if(!isalpha(c)) {
        a[i] = itoa(temp); 
        ++i;

        if(c == '\n') {
            *a[i] = '\n';
            j++;
        }
    }

    printf("Data is\n");

    for(int n = 0; n <= j; n++)
        printf("%s\n", a[n]);
}

char *itoa(int i) {

    char *s;

    while(i % 10 != 0) {
        *s++ = i / 10;            //save to s
        i = i % 10;               //removed saved part from i
}

    return s;
}

我编译了它并给出了上面的数据。我本应该按 control-D 告诉程序我已完成输入(EOF)，但程序以段错误 11 响应，之后，终端开始接受我的输入，就好像我这样写:

urw7RS:Desktop urw7rseeh8fr$        1    1125N660DL  ABQ           18     211     204    1250

终端告诉我找不到该命令。这是输出:

urw7RS:Desktop urw7rseeh8fr$ ./a.out
   1     833N619DL  ABQ           26     204     214    1250
   1    1125N660DL  ABQ           18     211     204    1250
   1    1589N678DL  ABQ           23     206     212    1250
   2     833N659DL  ABQ           18     204     194    1250
   2    1125N656DL  ABQ           23     211     210    1250
   2    1589N665DN  ABQ           19     206     212    1250
   3     833N686DA  ABQ           23     204     204    1250
   3    1125N692DL  ABQ           27     211     216    1250
   3    1589N635DL  ABQ           26     206     210    1250
   4     833N688DL  ABQ           21     204     206    1250
   4    1125N660DL  ABQ           18     211     221    1250
   4    1589N631DL  ABQ           28     206     209    1250
Segmentation fault: 11
urw7RS:Desktop urw7rseeh8fr$        1    1125N660DL  ABQ           18     211     204    1250
-bash: 1: command not found
urw7RS:Desktop urw7rseeh8fr$        1    1589N678DL  ABQ           23     206     212    1250
-bash: 1: command not found
urw7RS:Desktop urw7rseeh8fr$        2     833N659DL  ABQ           18     204     194    1250
-bash: 2: command not found
urw7RS:Desktop urw7rseeh8fr$        2    1125N656DL  ABQ           23     211     210    1250
-bash: 2: command not found
urw7RS:Desktop urw7rseeh8fr$        2    1589N665DN  ABQ           19     206     212    1250
-bash: 2: command not found
urw7RS:Desktop urw7rseeh8fr$        3     833N686DA  ABQ           23     204     204    1250
-bash: 3: command not found
urw7RS:Desktop urw7rseeh8fr$        3    1125N692DL  ABQ           27     211     216    1250
-bash: 3: command not found
urw7RS:Desktop urw7rseeh8fr$        3    1589N635DL  ABQ           26     206     210    1250
-bash: 3: command not found
urw7RS:Desktop urw7rseeh8fr$        4     833N688DL  ABQ           21     204     206    1250
-bash: 4: command not found
urw7RS:Desktop urw7rseeh8fr$        4    1125N660DL  ABQ           18     211     221    1250
-bash: 4: command not found
urw7RS:Desktop urw7rseeh8fr$        4    1589N631DL  ABQ           28     206     209    1250
-bash: 4: command not found
urw7RS:Desktop urw7rseeh8fr$ 

我做错了什么？

Answer 1

看起来终端是解释你的数据而不是处理它，所以它尝试像命令一样执行每一行，并且不存在像你的每行开头的数字这样的命令文件。您确定正在执行您的程序而不是包含数据的文件吗？

此外，所有指向字符串的 char* 指针均未分配，因此您会遇到段错误