How to convert a single char into an int [duplicate]

You can utilize the fact that the character encodings for digits are all in order from 48 (for ‘0’) to 57 (for ‘9’). This holds true for ASCII, UTF-x and practically all other encodings (see comments below for more on this).

Therefore the integer value for any digit is the digit minus ‘0’ (or 48).

char c = '1';
int i = c - '0'; // i is now equal to 1, not '1'

is synonymous to

char c = '1';
int i = c - 48; // i is now equal to 1, not '1'

However I find the first c - '0' far more readable.

Related Posts:

  1. outputting ascii table in C++
  2. std::string to char*
  3. Conversion from string to char – c++
  4. What is an unsigned char?
  5. How to convert a char array to a string?
  6. std::string to char*
  7. How to convert a std::string to const char* or char*
  8. getline() does not work if used after some inputs
  9. How can I convert const char* to string and then back to char*?
  10. Convert char* to string C++
  11. Comparing the values of char arrays in C++
  12. Convert char array to single int?
  13. How to sort with a lambda?
  14. casting int to char using C++ style casting
  15. C++ 2d char array to string
  16. Using cin for char array
  17. How do I simply compare characters in C++?
  18. Using cin to input a single letter into a char
  19. What is a segmentation fault?
  20. Regular cast vs. static_cast vs. dynamic_cast
  21. C++ std::priority_queue uses the lambda expression
  22. When to use reinterpret_cast?
  23. Expression must be a modifiable lvalue
  24. How to read a file line by line or a whole text file at once?
  25. Split a string using C++11
  26. error: expected unqualified-id error: Meaning and fix? [duplicate]
  27. How to track down a “double free or corruption” error
  28. undefined reference to `WinMain@16′
  29. How can I clear console
  30. TranslateName() function doesn’t work on win10
  31. How to use the PI constant in C++
  32. How to concatenate two strings in C++?
  33. Compiling C++11 with g++
  34. Setting an int to Infinity in C++
  35. What exactly is std::atomic?
  36. Separating class code into a header and cpp file
  37. Deep copy vs Shallow Copy
  38. C++ Fatal Error LNK1120: 1 unresolved externals
  39. Vector of structs initialization
  40. C++ deprecated conversion from string constant to ‘char*’
  41. Converting a vector to string
  42. std::string formatting like sprintf
  43. Sorting Characters Of A C++ String
  44. Sentinel while loop for C++
  45. How to ensure that a std::map is ordered?
  46. How to write C++ getters and setters
  47. std::out_of_range error?
  48. Checking cin input stream produces an integer
  49. libpng warning: iCCP: known incorrect sRGB profile
  50. C++: Expression must have a constant value when declaring array inside function
  51. What does ‘const static’ mean in C and C++?
  52. C++ wait for user input
  53. non-standard syntax; use ‘&’ to create a pointer to member
  54. How to shuffle a std::vector?
  55. Understanding glm::lookAt()
  56. How to get current timestamp in milliseconds since 1970 just the way Java gets
  57. What is the best open XML parser for C++?
  58. *** No rule to make target ‘class.cpp’, needed by `build/….x86/class.o` Stop. error in Ubuntu
  59. What’s the difference between opening a file with ios::binary or ios::out or both?
  60. Debug vs Release in CMake
  61. C++ Matrix Class
  62. access violation reading location c++
  63. C++ template constructor
  64. PlaySound in C++ Console application?
  65. Creation of Dynamic Array of Dynamic Objects in C++
  66. Compiling simple Hello World program on OS X via command line
  67. Cannot open output file, permission denied
  68. Strange error C2131: expression did not evaluate to a constant in VC 2015
  69. error: called object type ‘int’ is not a function or function pointer
  70. Hash function for a string
  71. Why I cannot cout a string?
  72. How do I return a char array from a function?
  73. c++ reading csv file
  74. Why do you use typedef when declaring an enum in C++?
  75. What is wrong with using goto?
  76. Double pointer array in c++
  77. Don’t understand static boolean behavior
  78. How to write std::string to file?
  79. Member declaration not found
  80. creating dynamic array of string c++
  81. How well is Unicode supported in C++11?
  82. The CXX compiler identification is unknown
  83. Is there a standard sign function (signum, sgn) in C/C++?
  84. C++ compiler error: “return type specification for constructor invalid”
  85. error: ISO C++ forbids in-class initialization of non-const static member
  86. Function call missing argument list to create pointer
  87. cannot specify explicit initializer for arrays
  88. What does ** mean in C++?
  89. Incomplete type is not allowed: stringstream
  90. How to determine the version of the C++ standard used by the compiler?
  91. Make / gcc cryptic error 2: how to have more information?
  92. REGSVR32: the module “xxxxx.dll” failed to load … dependent assembly could not be found
  93. Error: expression cannot be used as a function?
  94. What is a .h.gch file?
  95. MinGW .exe requires a few gcc dll’s regardless of the code?
  96. Converting bool to text in C++
  97. clearing a vector of pointers [duplicate]
  98. Evaluate a string with a switch in C++ [duplicate]
  99. C++ JSON Serialization
  100. stack around the variable…was corrupted

Leave a Comment