C++ Cannot Compile OpenCV Programs

#include "stdio.h"
# include "highgui.h"
# include "cv.h"

int main(intargc, char**argv){

    IplImage*img=cvLoadImage(argv[1]);

    cvNamedWindow("scrot.png", CV_WINDOW_AUTOSIZE);

    cvShowImage("scrot.png", img);

    cvReleaseImage(&img);

    cvDestroyWindow("scrot.png");

}

reg++-Wall-o "rei2-1" "rei2-1.cpp" (directory: /home/pi/Desktop/C)/tmp/ccWxBQc9.o:In function main': 
rei2-1.cpp: (.text+0x28): Undefined reference to cvLoadImage'
rei2-1.cpp: (.text+0x3c): Undefined reference to cvNamedWindow'
rei2-1.cpp: (.text+0x4c): Undefined reference to cvShowImage'
rei2-1.cpp: (.text+0x58): Undefined reference to cvReleaseImage'
rei2-1.cpp: (.text+0x60): Undefined reference to cvDestroyWindow'  
collect2:error:ld returned1 exit status compilation failure –