Question

我从我写的程序中得到了一些错误。我正在尝试制作一个程序，可以找到数据中的项目数，数据中的高值和低值，均值，中位数，模式，方差和标准差。

我得到的错误是错误：从（路径）filename.c引用的未解析的外部'_mean'

 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>

 void readData(float[],int count);
 float dataMean(float[],int count);
 float dataSd(float[],int count);
 float dataMin(float[],int count);
 float dataMax(float[],int count);
 float dataMedian(float[],int count);

int main()
{

    float data[200];
    int choice,count=0,i;

    do
    {
        printf("*****************************************************************\n");
        printf("*        This program will perform the following:               *\n");
        printf("* 1.Enter Data                                                  *\n");
        printf("* 2.Display the data and the following statistics:              *\n");
        printf("* The number of date item, the high and low values in the       *\n");
        printf("* data, the mean, median, mode, variance and standard deviation.*\n");
        printf("* 3.Quit the program                                            *\n");
        printf("*****************************************************************\n");
        printf("\n\nYour Choice: ");
        scanf("%d",&choice);
        printf("Enter one data item after each prompt.\n");
        printf("Enter -1 with  when you are done with data input.\n\n");

       switch(choice)
         {
            case 1:
                  readData(data,count);
                  break;
            case 2:
                printf("\nGiven data: \n");
                printf("%.2f ",data[i]);
                printf("\n\nTotal no of data items: %d",count);
                printf("\nHighest value in the data: %.2f",dataMax(data,count));
                printf("\nLowest value in the data: %.2f",dataMin(data,count));
                printf("\nMean: %.2f",dataMean(data,count));
                printf("\nMedian: %.2f",dataMedian(data,count));
                printf("\nStandard Deviation: %.2f",dataSd(data,count));
                printf("\nVariance: %.2f\n\n",pow((dataSd(data,count)),2));
                break;
            case 3:
                exit(0);
        }
    }while(1);


  getchar();
  return 0;
}


void readData(float data[],int count)
{
     int value = 0;
     int item[200];


     printf("Item #%d:\t",value++);
     scanf("%f",&item);

     while((item) != EOF)
  {

    printf("Item #%d:\t",value++);
    scanf("%f",&item);

  }
   return *item;
}
float dataMean(float *data,int count)
{
   int i;
   float mean=0.0;
   for(i=0;i<count;i++)
    {
     mean+=data[i];
    }

   return mean/count;
             }

float dataSd(float data[],int count)
{
    float avg=dataMean(data,count);
    float SD =0.0;
    int i;
    for(i=0;i<count;i++)
    {
        SD+= pow((data[i]-avg),2);
    }
    return sqrt(SD/count);
}

float dataMax(float data[],int count)
 {
    int i=0;
    float max=data[0];

    for(i=0;i<count;i++)
     if(max<data[i])
       max=data[i];


    return max;
}

float dataMin(float data[],int count)
{
    int i=1;
    float min=data[0];

    for(i =0;i<count;i++)

    if(min>data[i])
    min=data[i];
    return min;
}


float dataMedian(float data[],int count)
{
    int i,j;
    float tmp;
    for(i=0;i<count-1;i++)
     for( j=i+1;j<count;j++)
        if(data[i]>data[j])
        {
            tmp=data[i];
            data[i]=data[j];
            data[j]=tmp;
        }
       if(count%2==0)
         return (data[count/2-1]+data[count/2])/2;
       else
         return data[count/2];
    }

Answer 1

math.h中没有平均值（...）

float dataSd(float data[],int count)
{
    float avg=mean(data,count);
    float SD =0.0;
    int i;
    for(i=0;i<count;i++)
    {
        SD+= pow((data[i]-avg),2);
    }
    return sqrt(SD/count);
}

Answer 2

mean(data,count);

链接器告诉您，它无法找到mean()函数。没有这样的功能。

用C创建一个Mini Statistics程序

2 个答案: