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Nested printf (printf inside printf) in C
  • Difficulty Level : Easy
  • Last Updated : 13 Dec, 2018

Predict the output of the following C program with a printf inside printf.




#include<stdio.h>
   
int main()
{
   int x = 1987;
   printf("%d", printf("%d", printf("%d", x)));
   return(0);
}

Output :

198741

Explanation :
1. Firstly, the innermost printf is executed which results in printing 1987

2. This printf returns total number of digits in 1987 i.e 4. printf() returns number of characters successfully printed on screen. The whole statement reduces to :




printf("%d", printf("%d", 4));

3. The second printf then prints 4 and returns the total number of digits in 4 i.e 1 (4 is single digit number ).



4. Finally, the whole statement simply reduces to :




printf("%d", 1);

5. It simply prints 1 and output will be :

Output:

198741

So, when multiple printf’s appear inside another printf, the inner printf prints its output and returns length of the string printed on the screen to the outer printf.

This article is contributed by Rishav Raj. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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