C - Scanf 没有得到输入

Question

我是 C 的新手，遇到了一个问题。在我的代码中，我想获取用户的年龄、gpa 和字母等级。但是，当我运行代码时，它只获取年龄和 gpa 的输入，忽略了字母等级。它总共只要求 2 个输入而不是 3 个。但是如果我要单独检查输入而不是同时检查输入，它会正常运行。为什么会这样？

检查下面我的代码：

int main(void) {

  int age;
  double gpa;
  char grade;

  // int
  printf("Enter your age: ");
  scanf("%d", &age);

  // double
  printf("Enter your gpa: ");
  scanf("%lf", &gpa);

  // char
  printf("Enter your letter grade: ");
  scanf("%c", &grade);

  // prints
  printf("You are %d years old", age);
  printf("\nYour gpa is %f", gpa);
  printf("\nYour grade is %c", grade);

  return 0;
}

输出：

Enter your age: 12
Enter your gpa: 4.0
Enter your letter grade: You are 12 years old
Your gpa is 4.000000
Your grade is

Answer 1

   int main(void) {

  int age;
  double gpa;
  char grade;

  // int
  printf("Enter your age: ");
  scanf("%d", &age);

  // double
  printf("Enter your gpa: ");
  scanf("%lf", &gpa);
Getchar();

  // char
  printf("Enter your letter grade: ");
  scanf("%c", &grade);

  // prints
  printf("You are %d years old", age);
  printf("\nYour gpa is %f", gpa);
  printf("\nYour grade is %c", grade);

  return 0;
    }

您的成绩 scanf 语句正在读取上一条语句中的换行符。所以，在成绩声明之前添加一个 getchar() 读取换行符

Answer 2

把 scanf(" %c", &grade) 而不是 scanf("%c", &grade) 因为你需要在 %c 之前有一个空格来跳过当 scanf 停止在末尾时没有读取的换行符数

#include <stdio.h>

int main(void) {

  int age;
  double gpa;
  char grade;

  printf("Enter your age: ");
  scanf("%d", &age);

  printf("Enter your gpa: ");
  scanf("%lf", &gpa);

  printf("Enter your letter grade: ");
  scanf(" %c", &grade);

  printf("You are %d years old", age);
  printf("\nYour gpa is %f", gpa);
  printf("\nYour grade is %c", grade);

  return 0;
}

C - Scanf 没有得到输入

C - Scanf not getting input

c

scanf