100% C prog (comparatively efficient) to find norm-2 of a vector and display the result

#include<stdio.h>
#include<math.h>
void main()
{
    int i,n;
   float c[4], norm2c,total=0.0;
   // c is a vector whose norm has to be calculated
   printf("\n enter the no of rows of the column vector 1 to 4:"); /* we are assuming max size of the vector as 4*/
   scanf("%d",&n);
   for (i=0;i<n;i++)
   {
       printf("\n enter the c[%d] element:",i); /* it can be float number */
       scanf("%f",&c[i]);
       total=total+c[i]*c[i];
   }  /* till now we have entered the values of the vector,  squared each of the element and added them up*/
   /* now lets take square root to get the norm */
   norm2c=sqrt(total);
   printf("\n norm-2 of given vector= %f", norm2c);
       
   }//end of main

 /*this prog is efficient than the just previous one as it uses 1 for loop less

ఔట్పుట్  తెరమీద  

 enter the no of rows of the column vector 1 to 4:3
enter the c[0] element:-1
enter the c[1] element:1
enter the c[2] element:-1.0
norm-2 of given vector= 1.732051