CMPT 102 Lab #7

November 13-17 2006

This lab is designed to give further practice with structures

Practice Problem 1: Problem 7, p447 of you textbook

Create a structure type to represent a battery. A batteryType includes components, voltage, energy storage capacity (joules), and present energy stored (joules) and battery serial number (a 6 digit number). Define functions for input and output of a structure of type batteryType, and to compare two structures of type batteryType to see if they are equivalent batteries. To be equivalent the voltage and energy storage capacity must be the same. The present energy stored need not be the same and the serial numbers should not be the same. Also a function, powerDevice, which takes the current of an electrical device (amps), the time that device is to be powered (seconds) and a structure of type batteryType as arguments. The function, powerDevice determines if the is enough energy stored in the battery to power the device for the prescribed time. If there is not enough energy the function returns to value 0 to indicate that a different battery is needed for the task. It there is enough power in the battery, the required energy for running the device is subtracted from the present stored energy in the battery function then returns 1 to indicate that the battery should be used. Also define a function maxTime that takes a battery and the current of an electrical device as input parameters and returns the number of seconds the battery can operate that device before it is fully discharged. This function does not change any of the values in the batteryType structure. Write another function recharge that sets the present energy stored to the energy storage capacity of the batteryType structure. To relate these quantizes remember that power (Watts) is equal to Voltage (Volts)*Current (amps), and that energy (joules) is equal to power (Watts)*time (seconds). The prototypes for these functions should be:

void printBattery( struct batteryType btype);

struct batteryType readBattery(FILE *filep);

int compareBatteries(struct batteryType b1, struct batteryType b2);

int powerDevice(double current, int seconds, struct batteryType *b1);

int maxTime(double current, struct batteryType b1);

void rechargeBattery(struct batteryType *b1);

Create a main function that declares three batteryType structures. Read data from a file to initialize these structures to represent two 12-V car batteries with maximum energy storage of 5*10⁶ joules, and one 12V flashlight battery with a maximum energy storage capacity of 2*10⁴ joules. Print these batteries. Use the first car battery to power a 4-amp light for 15 minutes then print battery 1 again. Next find out how long that battery’s remaining energy could power an 8 amp device. After recharging the battery, print the battery again then redetermine how long it could operate the 8 amp device. Find out how long the second car battery could power a 6 amp lamp. Compare the two car batteries and determine they are equivalent, Compare a car battery to a 12-V flashlight battery and determine they are not equivalent.