C++ Practice Problems – Uppercase and Lowercase Conversion

Time Limit: 2s Memory Limit: 192MB

Problem Description

Input a string of characters, convert uppercase letters to lowercase, and output the original character if it is not uppercase.

Input Format

Any string (length within 100) is terminated by a newline.

Output Format

Output the corresponding lowercase for uppercase letters, and output the original character if it is not uppercase.

Sample Input

A123b

Sample Output

a123b

Code

#include <iostream>
#include <string>
#include <cctype>
using namespace std;
int main() {
    string s;
    getline(cin, s);
    for (char &c : s) {
        if (isupper(c)) {
            c = tolower(c);
        }
    }
    cout << s << endl;
    return 0;
}

Output Result

Methodology (1) Read Input: Read a line of string. (2) Process: Iterate through each character in the string: If it is an uppercase letter (‘A’ to ‘Z’), convert it to a lowercase letter (by adding 32 or using the built-in function). Otherwise, keep it unchanged. (3) Output Result: Output the processed string.Code Explanation (1) Read Input: Use getline to read a line of string, including spaces. (2) Process: Use a range-based for loop to iterate through each character, using isupper to check if it is an uppercase letter, and if so, convert it to lowercase using tolower. (3) Output Result: Directly output the processed string.Validation ExampleInput: A123bOutput: a123b

C++ Basic Tutorial Collection

C++ Basic Resources

1. C++ Output

2. C++ Variables

3. C++ Input

4. C++ Expressions

5. IF Statements

6. IF Applications

7. WHILE Loops

8. FOR Loops

9. Arrays

10. One-Dimensional Arrays

11. Two-Dimensional Arrays

12. C++ Functions

13. C++ File Operations – Writing Files

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