Explanation of How this program works
1. Every program starts from main() function.
2. printf() is a library function to display output which only works if #include<stdio.h>is included at the beginning.
3. Here, stdio.h is a header file (standard input output header file) and #include is command to paste the code from the header file when necessary. When compiler encounters printf() function and doesn't find stdio.h header file, compiler shows error.
4. Code return 0; indicates the end of program. You can ignore this statement but, it is good programming practice to use return 0;.
I/O of integers in C
#include<stdio.h>
int main()
{
int c=5;
printf("Number=%d",c);
return 0;
}