C primer plus(第六版）第六章源代码

第六章

/*  6.1   */
#include<stdio.h>
int main(void)
{
   
	long num;
	long sum = 0L;
	int status;
	
	printf("Please enter an integer to be summed ");
	printf("(q to quit): ");
	status = scanf("%ld",&num);         //一开始忘记给scanf（）内的 ld 加 %，导致直接跳过循环 
	while (status == 1)
	{
   
		sum = sum + num;
		printf("Please enter next integer (q to quit): ");
		status = scanf("%ld",&num);
	}
	printf("Those integers sum to %ld.\n",sum);
	
	return 0;
}

/*   6.2   */
#include<stdio.h>
int main(void)
{
   
	int n = 5;
	
	while (n < 7)
	{
   
		printf("n = %d\n",n);
		n++;
		printf("Now n = %d\n",n);
	}
	printf("The loop has finished.\n");
	
	return 0;
}

/*   6.3   */
#include<stdio.h>
int main(void)
{
   
	int n = 0;;
	
	while (n < 3)
		printf("n is %d\n",n);
		n++;
	printf("That's all this program does\n");
	
	return 0;
	
}

/*     6.4    */
#include<stdio.h>
int main(void)
{
   
	int n = 0;
	
	while (n++ < 3);
		printf("n is %d\n",n);
	printf("That's all this program does.\n");
	
	return 0;
}

/*      6.5    */
#include<math.h>
#include<stdio.h>
int main(void)
{
   
	const double ANSWER = 3.14159;
	double response;
	
	printf("What is the value of pi?\n");
	scanf("%lf",&response);
	while(fabs(response - ANSWER) > 0.0001)
	{
   
		printf("Try again!\n");
		scanf