In C++, isupper() and islower() are predefined functions used for string and character handling.cstring.h is the header file required for string functions and cctype.h is the headerfile required for character functions.
This function is used to check if the argument contains any uppercase letters such as A, B, C, D……….Z.
Syntax int isupper(int x)
Input : A Output : Uppercase
Input : a Output : Not uppercase
This function is used to check if the argument contains lowercase letters such as a, b, c, d, ……..z.
Syntax int islower(int x)
Input:A Output : Not Lowercase
Input : a Output : Lowercase
Application of islower(), isupper(), tolower(), toupper() function.
Given a string, task is to convert the characters in the string into opposite case, i.e. if a character is in lowercase, we need to convert it into uppercade and vice versa.
Input : GeekS Output :gEEKs Input :Test Case Output :tEST cASE
1. Traverse the given string character by character upto its length, check if character is in lowercase or uppercase using predefined function.
3. If lowercase, convert it to uppercase using toupper() function, if uppercase, convert it to lowercase using tolower() function.
4. Print the final string.
This article is contributed by Ayush Saxena. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
- unordered_multimap and its application
- C++ bitset and its application
- is_permutation() in C++ and its application for anagram search
- isspace() in C/C++ and its application to count whitespace characters
- Oracle Interview | Set 8 (On Campus for Application Developer)
- VMware Interview Experience | Set 5 (On-Campus for IT Application Developer)
- Maximum repeated frequency of characters in a given string
- Maximum number of strings that can be formed with given zeros and ones
- Generate string with Hamming Distance as half of the hamming distance between strings A and B
- Longest suffix such that occurrence of each character is less than N after deleting atmost K characters
- Maximum length prefix such that frequency of each character is atmost number of characters with minimum frequency
- Longest palindromic string possible after removal of a substring
- XOR of two Binary Strings
- Find Kth largest string from the permutations of the string with two characters