c++ string lowercase code example

Example 1: how to compare lower case character to uppercase cpp

for(int i=0;i<str.size();i++){
int c = str[i]; 
        if (islower(c))  
            str[i] = toupper(c);
}

Example 2: check if character in string is uppercase c++

if (isupper(str[i])) {
	// str[i] is uppercase
}

Example 3: convert whole string to lowercase c++

#include<bits/stdc++.h> 
using namespace std; 
main() { 
    string s = "Viet Nam"; 
    transform(s.begin(), s.end(), s.begin(), ::tolower); //lowercase
    cout << s << endl; 
}

Example 4: c++ string functions lowercase

transform(su.begin(), su.end(), su.begin(), ::toupper);
transform(sl.begin(), sl.end(), sl.begin(), ::tolower);