png (file="plot3.png")

c <- read.table("household_power_consumption.txt",header=TRUE,sep=";")

c$Date <- as.Date(c$Date,"%d/%m/%Y")

cv <- c[c$Date == "2007-02-01" | c$Date =="2007-02-02",]

cv$DateTime <- paste(cv$Date,cv$Time)

cv$DateTime <- strptime(cv$DateTime, "%Y-%m-%d %H:%M:%S")

with (cv,{

plot(DateTime,as.numeric(as.character(Sub_metering_1)), type="l",ylab="Energy Sub Metering",xlab="")

points(DateTime,as.numeric(as.character(Sub_metering_2)), type="l",col="Red")

points(DateTime,as.numeric(as.character(Sub_metering_3)), type="l",col="Blue")

legend("topright",pch="--",col=c("black","blue","red"),legend=c("Sub_metering_1","Sub_metering_2","Sub_metering_3"))

})

dev.off()