Twice the minimum in C (using pointers)

Question

My professor uses this site (e-olymp.com) that automatically grades your solution in % For this homework we have to use pointers to solve these tasks. I had a problem with this one:

The array of real numbers is given. Calculate the twice value of the minimum element in array.

Input First line contains the number n (n ≤ 100) of elements in array. Second line contains n real numbers - the elements of array. Each value does not exceed 100 by absolute value.

Output Print the twice value of the minimum element in array with 2 decimal digits.

My solution, works perfectly fine in compiler but gives 0%, idk where is the mistake, could you take a look at this one?

#include<stdio.h>
#include <malloc.h>
int z, x;
double fx;
int main(void){
    double *c = (double *)malloc(x*sizeof(double));
    scanf("%d", &x);
    fx=100;
    for(z=0; z<x; z++){
        scanf("%lf", c+z);
        if(fx>*(c+z)) fx=*(c+z); 
    }
    printf("%.2lf", fx*2);
    free(c);
    return 0;
}

Think about the *order* in which you do things... What is the value of `x` before you read it from the user? — Some programmer dude, Jan 24 '21 at 13:25
Also, why are you using `malloc.h`? Use `stdlib.h` if using `malloc`. — costaparas, Jan 24 '21 at 13:26
Also note that for *any* pointer or array `c` and index `z` the expression `*(c + x)` is *exactly* equal to `c[z]`. The latter is not only easier to read and understand, it's also less to write. — Some programmer dude, Jan 24 '21 at 13:26
And in C you [should not cast the result of `malloc`](https://stackoverflow.com/questions/605845/do-i-cast-the-result-of-malloc). — Some programmer dude, Jan 24 '21 at 13:27
Do you need the global variables here? All three of `z`, `x` and `fx` should be declared inside `main`. — costaparas, Jan 24 '21 at 13:27
Lastly, this exercise seems very contrived, as it doesn't need an array at all. — Some programmer dude, Jan 24 '21 at 13:28
Side note: always check the return value of `scanf`, and that of `malloc`. — costaparas, Jan 24 '21 at 13:33
Since you only look at each element once there is no need for an array. You can calculate the minimum as you read. — stark, Jan 24 '21 at 14:36

Twice the minimum in C (using pointers)

0 Answers0