C primer Plus Chap 02

C primer Plus 第二章代码与练习记录。

第二章 C 语言概述

• xt3.c

  #include <stdio.h>
  int main(void)
  {
  	int day,age;
  	printf("please enter your age:\n");
  	scanf("%d",&age);
  	day=365*age;
  	printf("your age is %d,about %d days.\n",age,day);
  	return 0;
  }

  输出结果：

  please enter your age:
  23
  your age is 23,about 8395 days.

• xt4.c

  #include <stdio.h>
  void print(void);
  int main(void)
  {
  	print();
  	print();
  	print();
  	printf("which nobody can deny!\n");
  	return 0;
  }
  
  void print(void)
  {
  	printf("for he's a jolly good fellow!\n");
  }

  输出结果：

  for he's a jolly good fellow!
  for he's a jolly good fellow!
  for he's a jolly good fellow!
  which nobody can deny!

• xt4a.c

  #include <stdio.h>
  void print1(void);
  void print2(void);
  int main(void)
  {
  	print1();
  	print1();
  	print1();
  	print2();
  	return 0;
  }
  
  void print1(void)
  {	
  	printf("for he's a jolly good fellow!\n");
  }
  
  void print2(void)
  {
  	printf("which nobody can deny!\n");
  }

  输出结果：

  for he's a jolly good fellow!
  for he's a jolly good fellow!
  for he's a jolly good fellow!
  which nobody can deny!

• xt5.c

  #include <stdio.h>
  int main(void)
  {
  	int toes,squared,cubed;
  	toes=10;
  	squared=toes*toes;
  	cubed=squared*toes;
  	printf("toes=%d,squared=%d,cubed=%d\n",toes,squared,cubed);
  	return 0;
  }

  输出结果：

  toes=10,squared=100,cubed=1000

• xt6.c

  #include <stdio.h>
  void smile(void);
  int main(void)
  {
  	smile();smile();smile();
  	printf("\n");
  	smile();smile();
  	printf("\n");
  	smile();
  	printf("\n");
  }
  
  void smile(void)
  {
  	printf("smile!");
  }

  输出结果：

  smile!smile!smile!
  smile!smile!
  smile!

• xt7.c

  /*C函数原型及其调用*/
  #include <stdio.h>
  void two(void);
  void one_three(void);
  int main(void)
  {
  	printf("starting now:\n");
  	one_three();
  	printf("done!\n");
  	return 0;
  }
  
  void one_three(void)
  {
  	printf("one\n");
  	two();
  	printf("three\n");
  }
  void two(void)
  {
  	printf("two\n");
  }

  输出结果：

  starting now:
  one
  two
  three
  done!