while循环和do循环、缓冲区、一维数组

/*
 *
 *
 *输入缓冲区管理
 *
 *
 * */
#if 0
#include<stdio.h>
int main (){
	int num = 0;
	printf("请输入一个数字：\n");
	scanf("%d",&num);
	scanf("%*[^\n]");
	scanf("%*c");
	printf("num=%d\n",num);
	printf("请输入一个数字：\n");
	scanf("%d",&num);
	printf("num=%d\n",num);
	return 0;	
}

#elif 0
/*
 *
 *输出缓冲区
 *
 *
 * */
#include<stdio.h>
int main (){
	printf("1");
	fflush(stdout);
	while (1){
	}
	return 0;
}


#elif 0

/*
 *
 *数组演示
 *
 * */
#include<stdio.h>
int main (){
	int arr[5]; 	//数组声明语句
	int num = 0;
	arr[2] = 10;
	for (num = 0;num <= 4;num ++){
		arr[num] = num;
	}
	for (num = 4;num >= 0;num --){
		printf(" %d ",arr[num]);
		}
	     printf("\n");
	return 0;
}

#elif 0
/*
 *
 *数组练习
 *
 *
 * */
#include<stdio.h>
int main (){
	int arr[5] = {0};
	int qty = 0,num = 0,sum = 0; 			//用户输入的数字个数qty <5
	printf("请输入数字个数：\n");
	scanf("%d",&qty);
	for (num = 4;num >= 0;num--){
		printf("请输入一个数字：\n");
		scanf("%d",&arr[num]);
		if (num == 5 - qty){
			//检查数组是否被填满
			break;
		}
	}
	for (num = 5 - qty;num <= 4;num++){
		printf("%d",arr[num]); 		//倒序显示用户输入的数字
	}
	printf("\n");
	for (num = 5 - qty;num <= 4;num++){
		sum += arr[num];
	}
	printf("求和结果是: %d  \n",sum);
	return 0;
}

#elif 0
/*
 *
 *得到7个1到36之间的随机数
 *将数字显示出来
 *
 * */
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main (){
	int num = 0,tmp = 0,cnt = 0,num1 = 0; 			//cnt 用于记录已经得到有效数字
	int arr[7] = {0},arr1[7] = {0};
	srand(time(0));
	/*for (num = 0;num <= 6;num++){
		arr[num] = rand() % 36 + 1;
		}//含有重复的数字
		*/
	do {
			tmp = rand() % 36 + 1;
			for (num = 0;num <= cnt - 1;num++){ 		//把新数字和以前得到的所有数字依次作对比
				if (tmp == arr[num]){
					break;
				}
			}
			if (num == cnt){
				arr[cnt] = tmp;
				cnt++;
			}
	}while(cnt < 7);
	for (num = 0;num <= 6;num++){
		printf(" %d",arr[num]);
	}
	printf("\n");
	for (num = 0;num <= 6;num++){
		printf("请输入一个数字：\n");
		scanf("%d",&arr1[num]);
	}
	cnt = 0;
	for (num = 0;num <= 6;num++){
		for (num1 = 0;num1 <= 6;num1++){
			if (arr[num] == arr1[num1]){
				cnt++;
				break;
			}
		}
	}
	printf("买对的数字个数%d\n",cnt);
	return 0;
}


#elif 0

#include<stdio.h>
int main (){
	int arr[5] = {0};
	printf("arr是%p\n",arr);
	printf("arr[0]是%p\n",&arr[0]);
	printf("sizeof(arr)=%ld\n",sizeof(arr));
	return 0;
}

#elif 0
#include<stdio.h>
int main (){
	int size = 0;
	printf("请输入一个数字:");
	scanf("%d",&size);
	int arr[size]; 		//变长数组
	printf("sizeof(arr)=%ld\n",sizeof(arr));
	return 0;
}


#elif 1
/*
 *
 *
 *二维数组
 *
 * */
#include<stdio.h>
int main (){
	int arr[3][2],cnt = 0;
   //	arr[1][0] = 0;
	int row = 0, col = 0;
	for (row = 0;row <= 2;row++){
		for (col = 0;col <= 1;col++){
			arr[row][col] = cnt;
			cnt++;
		}
	}
	for (row = 0;row <= 2;row++){
		for (col = 0;col <= 1;col++){
			printf(" %d ",arr[row][col]);
		}
		printf("\n");
	}
	return 0;
}
#endif