Toggle all characters in the string in C++

This program translates the characters of a string into uppercase. However, this task can be easily achieved by using the toUpper() method of the c++ class library. But in this program, we perform this by calculating the ASCII value of characters in uppercase. The Algorithm is as follows;


   Step-1: Declare the array of char
   Step-2: Check ASCII value of uppercase characters which must grater than A and lesser than Z
   Step-3: Check ASCII value of lower characters which must grater than A and lesser than Z

The toggleChar() method gets the array of characters as an input. Then, traverse through the loop to ensure whether the entered character ASCII value is in the between of the A to Z or not, as following;


 Live Demo

using namespace std;
void toggleChars(char str[]){
   for (int i=0; str[i]!='\0'; i++){
      if (str[i]>='A' && str[i]<='Z')
         str[i] = str[i] + 'a' - 'A';
      else if (str[i]>='a' && str[i]<='z')
         str[i] = str[i] + 'A' - 'a';
int main(){
   char str[] = "ajay@kumar#Yadav";
   cout << "String before toggle::" << str << endl;
   cout << "String after toggle::" << str;
   return 0;

The supplied string has almost all characters in lower case which will be converted in uppercase as following;


String before toggle::ajay@kumar#Yadav
String after toggle::AJAY@KUMAR#yADAV