plot4.R

source("load.R")
data <- load()
Sys.setlocale("LC_TIME", "C")

png(file="plot4.png")
par(mfrow = c(2,2))

plot(data$Time, data$Global_active_power,
     type = "l",
     xlab = "", ylab = "Global Active Power")

plot(data$Time, data$Voltage,
     type ="l",
     xlab = "datetime", ylab = "Voltage")

plot(data$Time, data$Sub_metering_1,
     type = "l",
     xlab = "", ylab = "Energy sub metering")
lines(data$Time, data$Sub_metering_2, col = "red")
lines(data$Time, data$Sub_metering_3, col = "blue")
legend("topright",
       legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"),
       col = c("black", "red", "blue"),
       lty = "solid",
       bty = "n")

plot(data$Time, data$Global_reactive_power,
     type = "l",
     xlab = "datetime", ylab = "Global_reactive_power")
dev.off()