puts() vs printf() for printing a string

In C, given a string variable str, which of the following two should be preferred to print it to stdout?

  1)  puts(str);
  2)  printf(str);

puts() can be preferred for printing a string because it is generally less expensive (implementation of puts() is generally simpler than printf()), and if the string has formatting characters like ‘%’, then printf() would give unexpected results. Also, if str is a user input string, then use of printf() might cause security issues (see this for details).
Also note that puts() moves the cursor to next line. If you do not want the cursor to be moved to next line, then you can use following variation of puts().

   fputs(str, stdout)

You can try following programs for testing the above discussed differences between puts() and printf().

Program 1

filter_none

edit
close

play_arrow

link
brightness_4
code

#include<stdio.h>
int main()
{
    puts("Geeksfor");
    puts("Geeks");
      
    getchar();
    return 0;
}

chevron_right


Program 2

filter_none

edit
close

play_arrow

link
brightness_4
code

#include<stdio.h>
int main()
{
    fputs("Geeksfor", stdout);
    fputs("Geeks", stdout);
      
    getchar();
    return 0;
}

chevron_right


Program 3

filter_none

edit
close

play_arrow

link
brightness_4
code

#include<stdio.h>
int main()
{
    // % is intentionally put here to show side effects of using printf(str)
    printf("Geek%sforGeek%s");  
    getchar();
    return 0;
}

chevron_right


Program 4

filter_none

edit
close

play_arrow

link
brightness_4
code

#include<stdio.h>
int main()
{    
    puts("Geek%sforGeek%s");    
    getchar();
    return 0;
}

chevron_right


Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



My Personal Notes arrow_drop_up


Article Tags :
Practice Tags :


18


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.