运算符、分支语句

#if 0
/*
 *
 * 操作符演示
 *
 * */
#include<stdio.h>
int main(){
	char ch=~0x92;
	int num=ch;
	printf("num=0x%x\n",num);
	printf("3&5=%d\n",3&5);
	printf("3|5=%d\n",3|5);
	printf("3^5=%d\n",3^5);
	printf("3<<2=%d\n",3<<2);
	num=0x80000000;
	printf("0x80000000>>2=0x%x\n",0x80000000 >> 2);
	printf("num=0x%x\n",num >> 2);
	return 0;
}


#elif 0
/*
 *
 * 地址相关操作符演示
 *
 *
 * */
#include<stdio.h>
int main(){
	int num=0;
	printf("&num=%p\n",&num);
	*(&num)=10;
	printf("num=%d\n",num);
	return 0;
}


#elif 0
/*
 *
 * 三目表达式演示、
 *
 */
#include<stdio.h>
int main(){
	int num=0;
	printf("请输入一个数字：\n");
	scanf("%d",&num);
	num=num >= 0 ? num : 0-num;
	printf("绝对值是%d\n",num);
	return 0;
}


#elif 0
/*
 * 显示从0到127之间的 整数，显示二进制
 *
 * */
#include<stdio.h>
int main(){
	int num=0;
	unsigned char tmp=0x80;
	printf("请输入数字0-127：\n");
	scanf("%d",&num);
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf(" %d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	tmp >>= 1;
	printf("%d", (num & tmp) != 0);
	printf("\n");
	return 0;
}


#elif 0
/*
 *
 * 类型转换演示
 *
 * */
#include<stdio.h>
int main(){
	printf("num=%d\n",sizeof(1 ? 1: 0.9));
	printf("num1=%d\n",-7+3<0);
	printf("num2=%d\n",-7+3u<0);
	printf("%d  %d\n",300,(char)300);
	return 0;
}

#elif 0
/*
 *
 *if 分支语句演示
 *
 * */
#include<stdio.h>
int main(){
	int num = 0;
	printf("请输入一个数字：\n");
	scanf("%d",&num);
	if(num > 0){
		printf("非负数\n");
	}
	else if(num<0){
		printf("负数\n");
	}
	else if(!num){
		printf("是0\n");
	}
	return 0;
}

#elif 0
/*
 *
 * if分支演示
 *
 * */
#include<stdio.h>
int main(){
	int num = 0;
	printf("请输入一个数字：\n");
	scanf("%d",&num);
	if (num < 0) {
		printf("负数\n");
	}
	else if (num >= 0 && (num & 1)) {
		printf("奇数\n");
	}
	else if (num >= 0 && !(num & 1)) {
		printf("偶数\n");
	}

	return 0;
}


#elif 1
/*
 *
 * 寻找最小数字
 *
 * */
#include<stdio.h>
int main(){
	int num1=0,num2=0,num3=0;
	printf("请输入三个数字：\n");
	scanf("%d%d%d",&num1,&num2,&num3);

	/*if (num2 > num1 && num3 > num1 ) {
		printf("最小数字是：%d\n",num1);
	}
	else if (num1 > num2 && num3 >num2) {
		printf("最小数字是：%d\n",num2);
	}
	else if (num1 > num3 && num2 > num3) {
		printf("最小数字是：%d\n",num3);
	}*/

	if (num1 > num2) {
		if (num2 > num3) {
			printf("最小数字是是%d\n",num3);
		}
		else {
			printf("最小数字是%d\n",num2);
		}
	}
	else{
		if (num1>num3) {
			printf("最小数字是%d\n",num3);
		}
		else {
			printf("最小数字是%d\n",num1);
		}
	}
	return 0;
}
#endif