#include <stdio.h>

/* subprogram prototypes - declarations */

int function1(int, float); /* 2 formal parameters of type int, float */
                           /* an integer value is returned */
float function2(int, float, int); /* 3 formal parameters of type int, float, 
                                     int */
                                  /* a float value is returned */
int function3(char, char); /* 2 formal parameters of type char, char */
                           /* an int value is returned */
void function4(char, int); /* 2 formal parameters of type char, int */
                           /* nothing is returned - procedure */
void function5(void); /* no formal parameters, i.e. void */
                      /* nothing is returned - procedure */
void function6(int *); /* 1 formal parameter of type address of an int */
                       /* nothis is returned - procedure */

int main(void)
{
  int num1, num2 = 4;
  float val1, val2 = 27.8;
  char let1, let2 = 'a';

  num1 = function1(2, 3.4);  /* actual parameters are the values 2, 3.4 */

  val1 = function2(num1, val2, 3); /* actual parameters are the values of
                                      num1, val2, and the value 3 */
  num1 = function3(let2, 'c'); /* actual parameters are the value of let2 and
                                  the value 'c' */
  function4(let2, num1); /* actual parameters are the values of let2 
                            and num1 */ 
  function5(); /* there are no actual parameters */

  function6(&num1); /* actual parameter is the address of the variable num1 */
} 

/* function header - 2 formal parameters named number, value of type int,
        float respectively. Return type is int. */
int function1(int number, float value)
{
  int num1;
 
  num1 = value;  /* this truncates the float to an integer */
  return (number * num1);
}

/* function header - 3 formal parameters named number1, value and number2 of
        type int, float, int.  Return type is float. */
float function2(int number1, float value, int number2)
{
  return (3.4 * 4);
}


/* function header - 2 formal parameters named letter1 and letter2 of type
        char, char. Return type is int */
int function3(char letter1, char letter2)
{
  return (1);
}


/* function header - 2 formal parameters named letter and number of type
        char, int. Return type is void - this functions acts like a 
        procedure */
void function4(char letter, int number)
{
   
}

/* function header - 0 formal parameters. Return type is void - this 
        functions acts like a procedure */
void function5(void)
{
}

/* function header - 1 formal parameter of type address of an integer. Return 
        type is void - this functions acts like a procedure */
void function6(int *number)
{
}