输出未在 C 中显示

Question

char DayName(int day_th)
{
  const char *DayName[] = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday" };
  return *DayName[day_th];
}

int main()
{
  int day_th=2;
  printf("What is your favorite day of the week? 1 is Sunday and 7 is Saturday: \n");
  printf("Day %d is a %s", day_th, DayName(day_th-1));
  return 0;
}

我正在编写一个输出类似于“第 2 天是星期一”的代码。我正在使用 VS 2019，编译器不会引发任何错误。但是，当我点击运行时，只显示“你最喜欢哪一天...行”，而不显示“第 2 天是星期一”。请帮忙！非常感谢。

Answer 1

您通过将错误类型的数据传递给 printf 调用了未定义的行为：char 被传递到预期 char* 的位置 (%s)。

函数DayName 应该返回数组const char* 的元素而不取消引用它们。

#include <stdio.h>

const char* DayName(int day_th)
{
  const char *DayName[] = {"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday" };
  return DayName[day_th];
}

int main()
{
  int day_th=2;
  printf("What is your favorite day of the week? 1 is Sunday and 7 is Saturday: \n");
  printf("Day %d is a %s", day_th, DayName(day_th-1));
  return 0;
}