#include <stdio.h>

void input (int *a, int *b, int *c);
float average (int d, int e, int f);
void output (float calc_avg);

void main()
{
    int a,b,c;
    float avg_val;
    
    input (&a, &b, &c);
        
    avg_val = average(a, b, c);
    output(avg_val);
}

void input (int *a, int *b, int *c)
{
    printf("\n\nPlease enter three integers: ");
    scanf("%d %d %d", a, b, c);
}
    
float average (int d, int e, int f)
{
    return ((float)(d+e+f)/3.0);
}
    
void output (float calc_avg)
{
    printf("\n\nThe average of the three values is: %f\n\n", calc_avg);
}