what is the purpose of #include <stdio.h> and what is %ld
stdio.h means standard input or output function which contains printf(), scanf() functions. %ld indicates long int
" #include <stdio.h> " is a preprocessor which tells the system that before compiling this program it have to include all the content from file "stdio.h" to this program. Just like v@msi😏😏 said "stdio" is a header file of C which contains defination of a functions like scanf(), printf() etc. Whereas "%ld" is a format specifier for data type "long int"