Each process has a non-empty array of values. Find the minimum global value, the rank of the process that holds it and its index on this process

Question

I have written this code from various sources. However, it still doesn't run and throws errors. I'm just a beginner, what am I doing wrong?

/* Minimum Global Value, Rank of the process */
#define LEN 1000

#include <stdio.h>
#include <omp.h>
#include <mpi.h>
#include <stdlib.h>
#include <assert.h>

int MPI_Reduce(const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype, MPI_Op op, int root, MPI_Comm comm);

int main(int argc, char *argv[]){

    float val[LEN];
    int count;
    int myrank, minrank, minindex, i;
    float minval;
    
    struct {
        float value;
        int index;
    } in, out;
    
    /* Local MINLOC */
    in.value = val[0];
    in.index = 0;
    for(i=1; i<count; i++) {
        if(in.value > val[i]) {
                in.value = val[i];
                in.index = i;
        }
    }
    
    /* Global MINLOC */
    MPI_Init( &argc, &argv );
    MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
    in.index = myrank * LEN + in.index;
    MPI_Reduce(in, out, 1, MPI_FLOAT_INT, MPI_MINLOC, root, comm);
    if(myrank == root) {
        minval = out.value;
        minrank = out.index / LEN;
        minindex = out.index % LEN;
    }
    
    MPI_Finalize();
    
return 0;
}

It throws various errors regarding the root, the structs and the MPI_Reduce arguments