c - 简单的 while 循环

Question

我的代码:

#include <stdio.h>
int main(void){
char input;
  while(1){
      printf("Repeat? [Y/N] ");
      scanf("%c", &input);
      if(input=='N' || input=='n'){
          break;
      }
  }
  return 0;
}

预期输出:

Repeat? [Y/N] y

Repeat? [Y/N] y

Repeat? [Y/N] n  //Program terminated

输出:

Repeat? [Y/N] Repeat? [Y/N] y

Repeat? [Y/N] Repeat? [Y/N] y

Repeat? [Y/N] Repeat? [Y/N] n //Program terminated

Answer 1

scanf 正在读取输入缓冲区中留下的 \n 字符(按 Enter 键时)。只需将 scanf 替换为

scanf(" %c", &input);  
//     ^A space before %c can skip any number of white-spaces