string c++ if letter is lowercase code example

Example 1: string c++ if letter is lowercase

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

Example 2: string c++ if letter is lowercase

str[i] = toupper(str[i]);

Example 3: string c++ if letter is lowercase

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

Example 4: isalpha c++

char test='a';
cout<<isalpha(test);