/* --------------------------------------------------------------------  
** Figure 6.24:  Using a switch.                         
** -------------------------------------------------------------------- 
*/
#include "tools.h"  
#define   MAXDROP   5.0      /* volts */                                

void main( void )                                               
{   
    int gauge;      /* selected gauge of wire */                                      
    float rho;      /* resistivity of selected gauge of wire */
    float amps;     /* current rating of appliance */
    float wlen;     /* length of wire needed */
    float drop;     /* voltage drop for selected parameters */ 

    banner();                                          
    puts( "\n Wire Gauge Adequacy Evaluation" );   
    printf( "\n Please choose gauge of wire:\n"                  
            "\t 12 gauge \n\t 14 gauge \n"                              
            "\t 16 gauge \n\t 18 gauge \n"                          
            " Enter selected gauge: " );                      
    scanf( "%i", &gauge );

    switch (gauge) {                                          
      case 12: rho = 5.211;     break;               
      case 14: rho = 8.285;     break;             
      case 16: rho = 13.17;     break;               
      case 18: rho = 20.95;     break;               
      default: fatal( " Gauge %i is not supported.", gauge );  
    }    
 
    printf( "\n Enter the current rating for the appliance, in amps: " );        
    scanf ( "%g", &amps );
    printf( "\n Enter the length of the wire, in meters: " );        
    scanf ( "%g", &wlen );
    drop = 2 * wlen / 1000 * rho * amps ;

    printf( "\n For %i gauge wire %g meters long and %g amp appliance,\n"
            " voltage drop in wire = %g volts.  (Limit is %g volts.) \n", 
            gauge, wlen, amps, drop, MAXDROP );

    if (drop < MAXDROP) printf( "\n Selected gauge is adequate.\n" );
    else printf( "\n Selected gauge is not adequate.\n" );
    bye();
}