#include <stdlib.h> #include <stdio.h> /* randomPixels -- create an image with pixels of random color The red, green, and blue values for each pixel are choosen randomly and independently. */ int main(int argc, char *argv[]) { int r, nrows, c, ncols, red, grn, blu; FILE *image; /* check the command line parameters */ if ( argc != 4 ) { printf("colorChip fileName.ppm nrows ncols\n"); return 0; } /* open the image file for writing in binary mode */ if ( (image = fopen( argv[1], "wb") ) == NULL ) { printf("file %s could not be created\n", argv[1]); return 0; } nrows = atoi( argv[2] ); if ( nrows < 1 ) { printf("number of rows must be positive\n"); return 0; } ncols = atoi( argv[3] ); if ( ncols < 1 ) { printf("number of columns must be positive\n"); return 0; } /* write out the PPM Header information */ fprintf( image, "P6 "); fprintf( image, "%d %d %d ", ncols, nrows, 255 ); srand( time(NULL) ); /* write out the pixel data */ for ( r=0; r<nrows; r++ ) for ( c=0; c<ncols; c++ ) { red = rand()%256; grn = rand()%256; blu = rand()%256; fputc( red, image ); fputc( grn, image ); fputc( blu, image ); } /* close the file */ fclose ( image ); return 1; }
Comments:
Using integer modulo division with rand()
does not produce the best random integers.
You might want to use randInt()
from section B of the puzzles.