My C program outputs undesired array values -

i've been tasked code program processes simple 1d array return element values, compiler has been behaving strangely; outputting more values have array elements.. it's not being compliant 1 of statements (one prints new line character every 8 elements) , not assigning largest value variable. think other 2 problems go away once first problem fixed, however.

here brief:

design, code , test program that:

1. fills 20 element array (marks) random numbers between 0 , 100.
2. prints numbers out 8 line
3. prints out biggest number, smallest number , average of numbers

and here code:

#include <stdio.h> #include <stdlib.h> #include <time.h>  int main(){      srand(time(null));      int marks[20];     int = 0;     int sum = 0;     int min;     int max;      for(i;i<=sizeof(marks);i ++){          marks[i] = rand() % 100;         sum += marks[i];          if(i % 8 == 0){             printf("\n");         }          printf("%d ", marks[i]);         if(marks[i]>max){             max = marks[i];         }         else  if(marks[i]<min){             min = marks[i];         }     }       printf("\n\nthe minimum value is: %d", min);     printf("\nthe maximum value is: %d", max);     printf("\n\nthe average value is: %d", sum / sizeof(marks));      return 0; } 

please can me correct output?

sizeof() function returns byte length of array, code "thinks" array 20 * whatever byte size ints on machine. want use i < 20 in loop or go

for (i;i<sizeof(marks)/sizeof(int); ++) { ... 

note not want <= operator in for loop, since arrays 0 indexed, marks[20] 1 beyond array.