Question

4. Write a function called mean that will return the average value of an integer array. The integer array and its length must be passed to the function as parameters.

5.Write a function called max that will return the index of the max value of an integer array. The integer array and its length must be passed to the function as parameters.

E.g. array = {1,2,3,4,5,6,7,8,9,0}

max = 9

index = 8

6.Write a function called variance that calculates and returns the variance of an array that is passed to it as a parameter. Also, pass the length of the array as a parameter.

variance = mean(array^2) - (mean(array))^2

array^2 = square of each element of the array

You must use the mean function above in your calculation.

c language

Answer 1

/*****************************************MaxIndex.c**********************************************/

#include<stdio.h>
#include<math.h>
int max(int array[], int size){
  
   int max = 0,i,index;
   for(i=0;i<size;i++){
      
       if(max<array[i]){
          
           max = array[i];
           index = i;
       }
   }
  
   return index;
}
int main(){
  
   int array[] = {1,2,3,4,5,6,7,8,9,0};
   int size = sizeof(array)/sizeof(array[0]);
   int maxIndex = max(array,size);
   printf("max index is: %d\n",maxIndex);
   return 0;
}

/*********************output******************/

max index is: 8

--------------------------------

/********************************ArrayMean.c***************************/

#include<stdio.h>
#include<math.h>
float mean(int array[],int size){
  
   float total = 0;
   int i;
   for(i=0;i<size;i++){
      
       total+=array[i];
   }

   return total/size;
}
int main(){
  
   int array[] = {1,2,3,4,5,6,7,8,9,0};
   int size = sizeof(array)/sizeof(array[0]);
   float meanOfArray = mean(array,size);
   printf("Mean is: %f\n",meanOfArray);
   return 0;
}

/********************output*******************/

Mean is: 4.500000

--------------------------------

/*************************Variance.c***********************/

#include<stdio.h>
#include<math.h>
float mean(int array[],int size){
  
   float total = 0;
   int i;
   for(i=0;i<size;i++){
      
       total+=array[i];
   }

   return total/size;
}
float variance(int array[],int size){
  
   int total = 0,i;
   for(i=0;i<size;i++){
      
       total+=pow(array[i],2);
   }
   float meanOfArraySquare = (float)total/size;
   float squareOfMean = pow(mean(array,size),2);
   return meanOfArraySquare - squareOfMean;
}
int main(){
  
   int array[] = {1,2,3,4,5,6,7,8,9,0};
   int size = sizeof(array)/sizeof(array[0]);
   float var = variance(array,size);
   printf("Variance is: %f\n",var);
  
   return 0;
}

/******************output*******************/

Variance is: 8.250000

--------------------------------

Please let me know if you have any doubt or modify the answer,Thanks:)