C编程: ouput two strings as two columns next to each other

Question

我对我用 C 编写的程序有疑问。我将在两列中并排写两个不同的字符串。我没有找到我的问题的明确答案，因为他们几乎总是给出长度或数量已知的数字示例。

我有两个字符串，最大长度为 1500 个字符，但对我来说长度未知。让我们为了学习而赋予他们这些值(value)观:

char string1[] = "The independent country is not only self-governed nation with own authorities.";
char string2[] = "This status needs the international diplomatic recognition of sovereignty.";

我想把它们并排写，列宽为二十个字符。我已将列之间的差异设置为常规“选项卡”。像这样:

The independent coun     This status needs th
try is not only self     e international dipl
-governed nation wit     omatic recognition o
h own authorities.       f sovereignty.

我已尝试使用以下代码，但它并不有效，因为我无法弄清楚如何使其适应字符串的长度。它也刚好适合写五行。我也收到以下错误。

谁能给我一个例子说明如何做到这一点，也许可以使用预定义的 c 函数以避免使用 for 循环。

void display_columns(char *string1, char *string2);

int main()
{ 
  char string1[] = "The independent country is not only self-governed nation with own authorities.";
  char string2[] = "This status needs the international diplomatic recognition of sovereignty.";

  display_columns(string1,string2);
}

void display_columns(char *string1, char *string2)
{
  int i,j;
  for(i=0;i<5;i++)
  {
     for(j=0+20*i;j<20+20*i;j++)
     {
       printf("%c",string1[j]);
     }

     printf("\t");

     for(j=0+20*i;j<20+20*i;j++)
     {
       printf("%c",string2[j]);
     }
  }
}

Answer 1

我想这是更通用的方法。

void print_line(char *str, int *counter) {

    for (int i = 0; i < 20; i++) {
        if (str[*counter] != '\0') {
            printf("%c", str[*counter]);
            *counter += 1;
        } 
        else { printf(" "); }
    }
}

void display_columns(char *string1, char *string2)
{
    int counter = 0, counter2 = 0;

    while (1) {

        print_line(string1, &counter);

        printf("\t");

        print_line(string2, &counter2);

        printf("\n");

        if (string1[counter] == '\0' && string2[counter2] == '\0') {
            break;
        }
    }
}