Preprocessing command section 3

 

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

#define	CORRECT "www.baidu.com"
void main()
{
	char str[40];
	int cmp(char* str1, char* str2);

	printf("Please enter the website you like the best:");
	scanf("%s", str);

#ifndef CORRECT
#define	CORRECT "www.baidu.com"
#endif // !CORRECT
	if (cmp(str, CORRECT) == 0)
	{
		printf("\nYeah!You are a smart man!\n\n");
	}
	else
	{
		printf("\nYou are a not good man!\n\n");
	}
}

int cmp(char* str1, char* str2)
{
	int i = 0, j = 0;
	while (str1[1])
	{
		while (str2[j] == str1[i])
		{
			i++;
			j++;
			if (!str2[j])
			{
				return 0;
			}
			j = 0;
			i++;
		}
		return -1;
	}
}

 

#if 1

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#define ROUND 0
#define PI 3.1415926


void main()
{
	int r;
	double s;

	printf("input a number:");
	scanf("%d", &r);
#if ROUND
	s = r * r * PI;
	printf("Area of round is:%6.5f\n\n", s);
#else
	s = r * r;
	printf("Area or square is:%6.5f\n\n",s);
#endif
}
#endif

  need Understanding printing %6.5f、%g How to choose