c基础1-变量、作用域

#define  _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

int main()
{
	printf("%c\n", 65 +32 + 1);
	printf("%d\n", sizeof(char));
	printf("%d\n", sizeof(short int));
	printf("%d\n", sizeof(int));
	printf("%d\n", sizeof(long int));
	printf("%d\n", sizeof(long long int));
	printf("%d\n", sizeof(float));
	printf("%d\n", sizeof(double));

	float weight = 16.6;
	double wei = 34.2;

	printf("%f ", weight);
	printf("%lf \n", wei); 

	scanf(" %f %lf", &weight, &wei);

	printf("%f ", weight);
	printf("%lf \n", wei);
	system("pause");
	return 0;
}

#define  _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>
int val = 100;

//声明外部符号(变量/函数)，告知编译器，该符号在其它文件或则当前文件的其它位置定义（分配内存），此处仅引用（仅声明变量名和函数原型）
extern int print_val();

//const定义的常变量  本质还是一个变量，只是值不可更改
const int a = 31;

//枚举常量
enum sex
{
	MALE,
	FEMALE,
	SECRET
};


int main()
{
	print_val();
	enum sex s = MALE ;
	printf("%d", s);
	system("pause");                               
	return 0;
}