Should I use printf(“\n”) or putchar(‘\n’) to print a newline in C?

It will make no difference which one you chose if you’re using a modern compiler[1]. Take for example the following C code.

#include <stdlib.h>
#include <stdio.h>

void foo(void) {
    putchar('\n');
}

void bar(void) {
    printf("\n");
}

When compiled with gcc -O1 (optimizations enabled), we get the following (identical) machine code in both foo and bar:

movl    $10, %edi
popq    %rbp
jmp _putchar                ## TAILCALL

Both foo and bar end up calling putchar('\n'). In other words, modern C compilers are smart enough to optimize printf calls very efficiently. Just use whichever one you think is more clear and readable.

  1. I do not consider MS’s cl to be a modern compiler.

Related Posts:

  1. How to do scanf for single char in C
  2. Sign extend a nine-bit number in C
  3. Break statement not within loop or switch in C
  4. How to properly malloc for array of struct in C
  5. Cache Simulator in C
  6. Where is the C auto keyword used?
  7. expected expression before ‘{‘ token
  8. Setting std=c99 flag in GCC
  9. C Vector/ArrayList/LinkedList
  10. Convert char array to a int number in C
  11. Bind failed: Address already in use
  12. Warning/error “function declaration isn’t a prototype”
  13. What is the difference between %f and %lf in C?
  14. What is stdin in C language?
  15. How to prevent multiple definitions in C?
  16. How to pass 2D array (matrix) in a function in C?
  17. error: ‘for’ loop initial declarations are only allowed in C99 mode [duplicate]
  18. How can you print multiple variables inside a string using printf?
  19. c – warning: implicit declaration of function ‘printf’
  20. C dynamically growing array
  21. Why should we check WIFEXITED after wait in order to kill child processes in Linux system call?
  22. How to compile makefile using MinGW?
  23. Mapping a numeric range onto another
  24. Why are hexadecimal numbers prefixed with 0x?
  25. Portable way to check if directory exists [Windows/Linux, C]
  26. too many arguments for format [-Wformat-extra-args]
  27. How to copy a char array in C?
  28. Simple way to check if a string contains another string in C?
  29. cast to pointer from integer of different size, pthread code
  30. Invalid type argument of unary ‘*’ (have ‘int’) Error in C
  31. Why do I get “cast from pointer to integer of different size” error?
  32. C subscripted value is neither array nor pointer nor vector when assigning an array element value
  33. error: too few arguments to function `printDay’ (C language)
  34. How to convert integer to char in C?
  35. Where to find the complete definition of off_t type?
  36. struct has no member named
  37. printf not printing to screen
  38. Initializing array of structures
  39. Still Reachable Leak detected by Valgrind
  40. Assembly x86 – “leave” Instruction
  41. What is the difference between array and enum in C ?
  42. What is signed integer overflow?
  43. When to use const char * and when to use const char []
  44. What do numbers using 0x notation mean?
  45. Can I create an Array of Char pointers in C?
  46. Does stack grow upward or downward?
  47. Convert Little Endian to Big Endian
  48. Excess elements of scalar initializer for pointer to array of ints
  49. error C2371: ‘functionname’ redefinition: different basic types
  50. How does one represent the empty char?
  51. How to write to a file using open() and printf()?
  52. note: previous implicit declaration of ‘point_forward’ was here
  53. Can I define a function inside a C structure?
  54. Where is the header file on Linux? Why can’t I find ?
  55. What exactly is meant by “de-referencing a NULL pointer”?
  56. Why is the sizeof(int) == sizeof(long)?
  57. getc() vs fgetc() – What are the major differences?
  58. Can’t understand the working of getint() in C as per K&R
  59. Lua – Number to string behaviour
  60. Tokenizing strings in C
  61. How to allocate array of pointers for strings by malloc in C?
  62. What tools are there for functional programming in C?
  63. typedef fixed length array
  64. How to format strings using printf() to get equal length in the output
  65. In C, what exactly happens when you pass a NULL pointer to strcmp()?
  66. “-bash: gcc: command not found” using cygwin when compiling c?
  67. How to format strings using printf() to get equal length in the output
  68. lseek/write suddenly returns -1 with errno = 9 (Bad file descriptor)
  69. What do \t and \b do?
  70. Why and when to use static structures in C programming?
  71. Where does linux store my syslog?
  72. Example of waitpid() in use?
  73. strtok segmentation fault
  74. Invalid write of size 1
  75. How to solve static declaration follows non-static declaration in GCC C code?
  76. realloc(): invalid next size when reallocating to make space for strcat on char *
  77. C Error: declaration shadows a local variable — Won’t let me repeatedly replace the value of my float variable
  78. Can a function return two values?
  79. C: warning: excess elements in array initializer; near initialization for ‘xxx’ ; expects ‘char *’, but has type ‘int’
  80. MIPS to C Translation
  81. write() to stdout and printf output not interleaved?
  82. Pointer to 2D arrays in C
  83. How to know what the ‘errno’ means?
  84. Split string with multiple delimiters using strtok in C
  85. Printf was not declared in this scope
  86. warning: missing terminating ” character [enabled by default]
  87. How to free memory from char array in C
  88. Can I get Unix’s pthread.h to compile in Windows?
  89. Initializing 2D char array in C
  90. Pointer to a string in C?
  91. FFT in a single C-file 
  92. Process exited with return value 3221225477
  93. gdb: No symbol “i” in current context
  94. How do I check if a string contains a certain character?
  95. malloc(sizeof(int)) vs malloc(sizeof(int *)) vs (int *)malloc(sizeof(int))
  96. %p Format specifier in c
  97. Level vs Edge Trigger Network Event Mechanisms
  98. “Nothing to be done for makefile” message
  99. Convert Char to String in C
  100. What is the difference between signed and unsigned int

Leave a Comment

tech