///////////////////////////////////
//
// program_3 project
//
// created 8/12/21 by tj
// rev 0
//
///////////////////////////////////
//
// Program to provide various calculations w/ functions
//
// Reads in a values for val1 and val2
// Reads in the desired operation
// Provides the result
//
// inputs: 2 values for val1 and val2, a character for the operation
// outputs: prints result of val1 operation val2
//
///////////////////////////////////

#include "mbed.h"
#include <stdio.h>                      // only needed when printing

// function prototypes
float get_val(char side);
char get_op(void);
void calc_print_results(float val_l, float val_r, char oper);

int main(void){
    setbuf(stdout, NULL);  // disable buffering when printing

    // splash 
    printf("\n\nprogram_3\n");
    printf("Using Mbed OS version %d.%d.%d\n\n", 
            MBED_MAJOR_VERSION, MBED_MINOR_VERSION, MBED_PATCH_VERSION);
    printf("Welcome to my calculator program (using functions)\n\n");
    
    float val1;
    float val2;
    char operation;

    // infinte loop
    while(1){       
        // ask for and read in values and operation
        val1 = get_val('L');
        val2 = get_val('R');
        operation = get_op();
            
        calc_print_results(val1, val2, operation);
    }// end while
            
   return 0;
}// end main

float get_val(char side){
    float val;
    
    // ask for and read in value
    printf("Please enter a value for %c side of the operation ", side);
    scanf("%f", &val);
    
    return val;
}// end get_val

char get_op(void){
    char op;
    
    printf("Please enter the operation requested \(+ - * /): ");
    scanf(" %c", &op);
    
    return op;
}// end get_op

void calc_print_results(float val_l, float val_r, char oper){
    float result;
    
    // select the calculation and execute
    switch(oper){
        case '+':
            result = val_l + val_r;
            printf("%f %c %f = %f\n\n", val_l, oper, val_r, result);
            break;
        case '-':
            result = val_l - val_r;
            printf("%f %c %f = %f\n\n", val_l, oper, val_r, result);
            break;
        case '*':
            result = val_l * val_r;
            printf("%f %c %f = %f\n\n", val_l, oper, val_r, result);
            break;
        case '/':
            result = val_l / val_r;
            printf("%f %c %f = %f\n\n", val_l, oper, val_r, result);
            break;
        default:
            printf("invalid operation\n\n");
            break;
    } // end switch 
    
    return;
}// end calc_print_results