目的

代码说明：

purpose merges two PGM gray-scale images, the first will be in the upper-left half, the second one in the lower-right half compile gcc -g -o diagonal_merge diagonal_merge.c -lpgm -lpbm -lm -purpose merges two PGM gray-scale images. the first will be in the upper-left half, the second one in the lower-right half compile g cc-g-o diagonal_merge diagonal_merge.c-RT m-lpbm- lm