tolower() Prototype
int tolower(int ch);
The tolower() function converts ch to its lowercase version if it exists. If the lowercase version of a character does not exist, it remains unmodified. The uppercase letters from A to Z is converted to lowercase letters from a to z respectively.
The behaviour of tolower() is undefined if the value of ch is not representable as unsigned char or is not equal to EOF.
It is defined in <cctype> header file.
tolower() Parameters
ch: The character to convert
tolower() Return value
The tolower() function returns a lowercase version of ch if it exists. Otherwise it returns ch.
Example: How tolower() function works
#include <cctype>
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int main()
{
char str[] = "John is from USA.";
cout << "The lowercase version of \"" << str << "\" is " << endl;
for (int i=0; i<strlen(str); i++)
putchar(tolower(str[i]));
return 0;
}
When you run the program, the output will be:
The lowercase version of "John is from USA." is john is from usa.