程序能正常运行,但为什么这里会报错?
//检测用户是不是只输入了一个大写字母
#include <stdio.h>
#include <ctype.h>
int main(void)
{
char ch;
printf("Please enter an uppercase letter to start:");
while (scanf_s("%c", &ch)) //此行报了黄色警告
{
if (ch == '\n') //检测首字符是否为换行符
{
printf("Please enter an uppercase letter!\n");
continue;
}
else if (getc(stdin) != '\n') //检测是否有多余的字符
{
printf("Please enter an uppercase letter!\n");
while (getchar() != '\n')
;
continue;
}
else if (!isupper(ch)) //检测是否为大写字母
{
printf("Please enter an uppercase letter!\n");
continue;
}
printf("Done");
}
return 0;
}