[数据结构与算法]C语言练习(十四)

1. 输入10个整数，计算其最大值和最小值，并交换它们所在数组中的位置

#include"stdio.h"
#define SIZE 10

void swap(int* a, int* b){
	int temp;
	temp = *a;
	*a = *b;
	*b = temp;
}

void input(int num[]){
	int i=0;
	for(;i<SIZE;i++)
		scanf("%d",num+i);
}

void max_min(int num[]){
	int i,max,min,maxpos,minpos;
	i = maxpos = minpos = 0;
	max = min = num[0];
	for(i=1;i<SIZE;i++){
		if(num[i] > max){
			max = num[i];
			maxpos = i;
		}
		else if(num[i] < min){
			min = num[i];
			minpos = i;
		}
	}
	swap(num+maxpos,num+minpos);
}

int main(){
	int i = 0;
	int num[SIZE];
	input(num);
	max_min(num);
	printf("交换后: \n");
	for(;i<SIZE;i++)
		printf("%4d",num[i]);
	return 0;
}

2. Fibonacci数列

#include"stdio.h"

//递归
int fib(int n){
	if(n==1||n==2)
		return 1;
	else return fib(n-1)+fib(n-2);
}

//循环
int _fib(int n){
	int num[n],i;
	num[0] = num[1] = 1;
	for(i=2;i<n;i++)
		num[i] = num[i-1] + num[i-2];
	return num[n-1];
}


int main(){
	int i;
	for(i=1;i<10;i++)
		printf("%d! = %4d\t\t%d! = %4d\n",i,fib(i),i,_fib(i));
	return 0;
}

3. 输入年月日，计算并输出它是这一年的哪一天

#include"stdio.h"

int isRun(int year){
	//是否是闰年
	if((year%4==0&&year%100!=0)||year%400==0)
		return 1;
	return 0;
}
int Day(int arr[], int month, int day){
	int i = 0,days = 0;
	for(;i<month-1;i++)
		days += arr[i];
	days += day;
	return days;
}

int YearToDay(int year, int month, int day){
	int arr1[] = {31,28,31,30,31,30,31,31,30,31,30,31};
	int arr2[] = {31,29,31,30,31,30,31,31,30,31,30,31};
	if(isRun(year))
		return Day(arr2,month,day);
	else return Day(arr1,month,day);
}

int main(){
	int year,month,day;
	printf("输入年月日: ");
	scanf("%d %d %d",&year,&month,&day);
	printf("第%d天\n",YearToDay(year,month,day));
	return 0;
}

4. 输入某年的第几天，计算并输出它是这一年的第几月第几日

#include"stdio.h"

int isRun(int year){
	//是否是闰年
	if((year%4==0&&year%100!=0)||year%400==0)
		return 1;
	return 0;
}
void Date(int arr[], int *month, int *day){
	int i = 0;
	while(*day > arr[i]){
		*day -= arr[i];
		*month += 1;
		i++;
	}
		
}

void YearToDay(int year, int* month, int* day){
	int arr1[] = {31,28,31,30,31,30,31,31,30,31,30,31};
	int arr2[] = {31,29,31,30,31,30,31,31,30,31,30,31};
	if(isRun(year))
		Date(arr2,month,day);
	else Date(arr1,month,day);
}

int main(){
	int year,month,days;
	month = 1;
	printf("某年第几日: ");
	scanf("%d %d",&year,&days);
	YearToDay(year,&month,&days);
	printf("%d月 %d日\n",month,days);
	return 0;
}

5. 输入10个数，计算平均数，中位数，众数

#include"stdio.h"
#define MAXSIZE 100
#define N 40

void input(int num[]){
	int i=0;
	for(;i<N;i++)
		scanf("%d",num+i);
}
//平均数
int average(int num[]){
	int sum = 0,i = 0;
	while(i<N){
		sum += num[i];
		i++;
	}
	return sum/N;
}
//众数
int most(int num[]){
	int count[MAXSIZE] = { 0 };
	int i = 0,maxpos = 0,max = 0;
	while(i<N){
		count[num[i]]++;
		i++;
	}
	i=0;
	while(i<N){
		if(count[num[i]] > max){
			maxpos = i;
			max = count[num[i]]; 
		}
		i++;
	}
	return num[maxpos];
}
void sort(int num[]){
	int i,j;
	for(i=0;i<N;i++){
		for(j=i;j<N;j++){
			if(num[i] > num[j]){
				int temp;
				temp = num[i];
				num[i] = num[j];
				num[j] = temp;
			}
		}
	}
}
//中位数
int middle(int num[]){
	sort(num);
	if(N%2==0)
		return (num[N/2] + num[N/2-1]) / 2;
	else return num[N/2];
}
int main(){
	int num[N];
	input(num);
	printf("平均数: %2d\t众数: %2d\t中位数:%2d\n",average(num),most(num),middle(num));
	return 0;
}