# High School Mathematics Extensions/Mathematical Programming/Exercise 1: Implementing Commands

## Explanation

Includes

Type Definitions

Function Prototypes

Global Variables

Function Definitions

## Code to change

Add and replace the following code:
```//function definitions
//...
int get_integer()
{
int ret_val;
char lastpress;

cprintf("Enter integer: ");
cscanf("%i",&ret_val);
lastpress=getch();
cprintf("\n");
return ret_val;
}
//...
void execute_command(char command)
{
switch (command)
{
case '/':   output_divide();
break;
case '%':   output_modulus();
break;
case '=':   output_values();
break;
case 'r':
case 'R':   r=get_integer();
output_values();
break;
case 'l':
case 'L':   l=get_integer();
output_values();
break;
case 'x':
case 'X':   done=TRUE;
break;
}
}
void output_divide()
{
if (r > 0)
{
cprintf("%d / %d = %d.\n",l,r,l/r);
}
else
{
cprintf("l = %d, r = %d. Please set r to a value other than 0.\n",r,l);
}
}
void output_modulus()
{
if (r > 0)
{
cprintf("%d %% %d = %d.\n",l,r,l%r);
}
else
{
cprintf("l = %d, r = %d. Please set r to a value other than 0.\n",r,l);
}
}
void output_values()
{
cprintf("l = %d, r = %d.\n",l,r);
}
```