C程序在第一次getchar（）后关闭

Question

为什么第一次输入后会关闭以下代码段？：

#include <stdio.h>
int main( ) {

   int a;
   int b;
   printf( "Enter a first value :");
   a = getchar( );

   printf( "You entered: ");
   putchar( a );

   printf( "\n Enter a second value :");
   b = getchar( );
   return 0;
}

打印后程序关闭

"Enter a second value :"

Answer 1

b = getchar( );将b分配给第一个输入的输入流中留下的换行符。

Answer 2

检查getchar的返回

while (((b = getchar()) != '\n') && (b != EOF)) { }

检查它是否同时调用getchar

int main()
{
   int a;
   int b;
   printf( "Enter a first value :");
   while (((a = getchar()) != '\n') && (a != EOF)) { }

   printf( "You entered: ");
   putchar( a );

   printf( "\n Enter a second value :");
   while (((b = getchar()) != '\n') && (b != EOF)) { }
   return 0;
}