C Challenge: Self-Printing Program

[The_Big_K]

Source: Programming Challenges - Self-Printing Program - Cprogramming.com


Here's a nice challenge for all you programming freaks.

Write a program that, when run, will print out its source code. This source code, in turn, should compile and print out itself.

Discuss the code with fellow CEans in this thread. Googling is good, but it doesn't add value to your knowledge.

[The_Big_K]

Hah, No one?

Too tough?

[ash]

That sounds doable Have a function to copy itself and read out its source code.

*rubs chin*

[anuragh27crony]

Good question...this question i have encountered....during my placements.....

Simple technique is ...to use %s in a pointer to char which contains itself while printing.

char *temp="include<stdio.h> void main() { char *temp=%s ...and so on";

[bayazidahmed]

Originally Posted by The_Big_K

Hah, No one?

Too tough?

Nah! Too easy.

[The_Big_K]

Alright, alright!

Why don't you help others come up with a solution then?

[Ashutosh_shukla]

If the following code is saved as PROG1.C then on running this code output is the code itself.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
void main()
{
 FILE *fp;
 char str[80];
 int i=0;
 clrscr();
 fp=fopen("PROG1.C","r");
 if(fp==NULL)
 {
  printf("File could not be opened.");
  getch();
  exit(1);
 }
 while(fgets(str,80,fp)!=NULL)
 {
  i++;
  printf("%d",i);
  printf("%s",str);
 }
 getch();
}

[anusha.p.s]

Execution of above code always says that "file cannot be opened"

[Ashutosh_shukla]

you save it as prog1.c in bin folder of turbo c then run it

[muts]

#include <stdio.h>
char *program = "#include <stdio.h>%cchar *program = %c%s%c;%cint main()%c{%c
printf(program, 10, 34, program, 34, 10, 10, 10, 10, 10, 10);%c return 0;%c}%c";
int main()
{
printf(program, 10, 34, program, 34, 10, 10, 10, 10, 10, 10);
return 0;
}

tell me about that