一维数组

读入一个一维数组，并求出平均值。

#include<stdio.h>
int main()
{
    int i， n;
	float average, totalscore = 0;
//将int score[n]放在这程序运行不出来
	printf("Please enter a number:");
	scanf("%d", &n);
//读入数组
	int score[n];	
	printf("Please enter numbers:");
	for(i = 0; i < n; i++)
	{
		scanf("%d", &score[i]);
		totalscore += score[i];
	}
	average = totalscore/n;
	printf("average = %f", average);
	return 0;
}

二维数组

<平年，闰年>

#include<stdio.h>
#define MONTHS 12                                 //宏定义
int main()
{
	int month, year;
	int days[2][MONTHS] = {{31,28,31,30,31,30,31,31,30,31,30,31},
	                       {31,29,31,30,31,30,31,31,30,31,30,31}};
	do{
		printf("Please enter year, month:");
		scanf("%d,%d", &year,&month);
	}while(month<1||month>12);                             //处理不合法数据的输入
	if(((year%4 == 0) && (year%100 != 0) ) || (year%400 == 0) )     //闰年
	printf("The number of days is %d", days[1][month-1]);
	else
	printf("The number of days is %d", days[0][month-1]);
	return 0;                      
} 

向函数传递数组

向函数传递一维数组<输入成绩，求平均分>

#include<stdio.h>
#define N 40           //宏定义，数组中可以输入40个元素

void ReadScore(int score[], int n);    //int ReadScore()也可以
float AverScore(int score[], int n);      //函数声明一定不要写在main函数里面
int main()
{
	int n;	         
	int score[N];               //声明时填入N
	float aver;
	printf("please enter the number of class:");   // n<=N，即<40
	scanf("%d", &n);
	ReadScore(score, n);
	aver = AverScore(score, n);            //调用函数中只写数组名
	printf("The average score is %f", aver);
	return 0;
}

//输入成绩
void ReadScore(int score[], int n)
{
	int i;
	printf("Please enter score:");
	for(i = 0; i < n; i++)
	{
		scanf("%d", &score[i]);
	}
}

//求平均分
float AverScore(int score[], int n)
{
	int i;
	float average,sum;
	for(i = 0; i < n; i++)
	{
		sum += score[i];
	}
	average = sum/n;
	return average;
}

当输入成绩为负时，表示输入结束，并输出平均分和输入的学生人数

#include<stdio.h>
#define N 40
//ReadScore函数变化，声明变化
int ReadScore(int score[]);
float AverScore(int score[], int n);
int main()
{
	int n, score[N];
	float average;

	n = ReadScore(score);
	printf("The number of total students is %d\n", n);  //ReadScoer函数返回输入学生的人数
	
	average = AverScore(score, n);
	printf("The average of score is %f", average);
	return 0;
} 

int ReadScore(int score[])
{
	int i = -1;      // i 的初始值 -1，保证循环体内 i 增 1 后，数组下标从 0 开始

    do{
    	i++;
	    printf("Please enter score:");   //printf函数放在do循环外，程序不能正常运行 
    	scanf("%d", &score[i]);
	}while(score[i]>0);
 //数组中元素的个数应该是 1+1 个，但最后一个 <0 作为结束的标记值，不算入学生成绩
	return i;     
}

float AverScore(int score[], int n)
{
	int i;
	float sum = 0,aver;
	for(i =0; i < n; i++)
	{
		sum += score[i];
	}
	aver = sum/n;
	return aver;
}

输入成绩，为负结束，打印最高分

#include<stdio.h>
#define N 40
int ReadScore(int score[]);

int FindMax(int score[], int n);
int main()
{
	int n, score[N], max;
    n = ReadScore(score);
	printf("The number of total students is %d\n", n);
	
	max = FindMax(score, n);
	printf("The highest score is %d\n", max);
	return 0;
} 

int ReadScore(int score[])
{
	int i = -1;

    do{
    	i++;
	    printf("Please enter score:");
    	scanf("%d", &score[i]);
	}while(score[i]>0);
	return i;
}

//找出最高分
int FindMax(int score[], int n)
{
	int max,i;
	max = score[0];
	for(i = 1; i < n; i++)
	{
		if(score[i] > max);
		max = score[i];
	}
	return max;
}