C++ Program To Convert Lowercase into Upper case

 

Program:

#include <iostream>
using namespace std;

string lowerToUpper(string s)
{
    string ans;
    for(int i = 0; i < s.length(); i++)
    {
	//if a character of string is in lower case
        if(s[i] >= 'a' && s[i] <= 'z')
        ans += s[i]-32;

	//if a character is uppercase, digit, space or underscore
        else
        ans += s[i];
    }
    return ans;
}

int main()
{
    string s = "hello world";
    cout << lowerToUpper(s);

    return 0;
}

Output:

HELLO WORLD

If you want to convert uppercase to lowercase then instead of addition, subtract s[i] with 32.

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