c - 在没有数组的情况下读取整数和/或字符

Question

我需要一个一个地读取一个整数，直到读取到一个'$'，然后判断最大，最小等等。我可以使用字符变量并执行它，但它适用于从 0 到 9 的数字。但是我如何读取两位或更多位的整数并同时检测 '$' - 我使用了 char *，但我猜它相当于一个数组，我不应该在这里使用它。此外，char 包含单个数字/char，因此不适合更大的数字。我该怎么办？

Answer 1

没有数组，没有指针，没有棘手的逐字符读取和转换。只是简单的 scanf 和 getchar。

#include <stdio.h>

int main()
{
    int newValue=0;        /* value being acquired */
    int max;               /* current maximum value */
    int min;               /* current minimum value */
    int firstAcquired=0;   /* boolean flag set to 1 after first acquisition */
    int ch;                /* used as temporary storage for the getchar() */
    for(;;)
    {
        /* scanf returns the number of successfully acquired fields; here if it
           returns 0 means that the value couldn't be acquired */
        if(scanf("%d",&newValue)==0)
        {
            /* scanf failed, but it's guaranteed it put the offending character
               back into the stream, from where we can get it */
            ch=getchar();
            if(ch=='$' || ch==EOF)
                break;
            else
            /* from here to the break it's just to handle invalid input and EOF
               gracefully; if you are not interested you can replace this stuff
               with a random curse to the user */
            {
                puts("Invalid input, retry.");
                /* Empty the buffer */
                while((ch=getchar())!='\n' && ch!=EOF)
                    ;
            }
            /* if it's EOF we exit */
            if(ch==EOF)
                break;
        }
        else
        {
        /* Everything went better than expected */
            if(!firstAcquired || newValue>max)
                max=newValue;
            if(!firstAcquired || newValue<min)
                min=newValue;
            firstAcquired=1;
        }
    }
    if(firstAcquired)
    {
        printf("The maximum value was %d\n", max);
        printf("The minimum value was %d\n", min);
    }
    return 0;
}