c - C中的编译器错误，: Expected Expression错误

Question

我遇到了一个我真的不知道如何解决的问题。我主要使用Python编写代码，这是我的第一个C语言程序。

#include <stdio.h>

int ask(void) {
  scanf("Var");
  return 0;
}

int count(ask) {
  scanf("number1");
  return 0;
}

int main(void) {
  printf("This is my first program!\n");
  printf("I hope this program turns out well.");
  printf("I don't really know what to do, but i think im progressing.\n");
  printf("But yeah, This is my first program.\n");
  printf("Type an Number");
  ask();
  count(ask());
  printf("Thanks!");
  printf(%count%);
  return 0;
}

但是，我不断收到错误消息。

main.c:22:10: error: expected expression
  printf(%count%);
         ^
main.c:22:17: error: expected expression
  printf(%count%);
                ^
2 errors generated.
compiler exit status 1

我想要它做的是，用户键入一个数字，然后打印出该数字。虽然还不完整。我希望它写数字1-用户输入，当数字正确时，它会打印“您的数字是:”(数字)

Answer 1

问题(正如已经指出的那样)是您实际上并没有从scanf()调用中获取和存储值。此外，printf(%count%)不是有效的C语法。您需要使用printf("%d", count)。
将所有内容放在一起:

#include <stdio.h>

int ask(void) {
  int input_number;
  scanf("%d", &input_number);
  getchar();  # This is so that the '\n' in is read when you hit Enter
  return input_number;
}

int main(void) {
  printf("This is my first program!\n");
  printf("I hope this program turns out well.");
  printf("I don't really know what to do, but i think im progressing.\n");
  printf("But yeah, This is my first program.\n");
  printf("Type an Number");
  int input_number = ask();
  printf("Thanks!");
  printf("The number you entered is %d\n", input_number);
  return 0;
}

为了避免犯这样的错误，需要阅读一些内容: printf教程: https://www.tutorialspoint.com/c_standard_library/c_function_printf.htm scanf教程: https://www.tutorialspoint.com/c_standard_library/c_function_scanf.htm