Функции tolower,islower,isupper

#include <iostream>
#include <cctype>
using namespace std;
 
/* tolower toupper isupper */
 
int main(){
        char c = 'a';
        
        c = toupper(c);
        printf("Char %c is %s\n", c, (isupper(c)) ? "big" : "small");
        c = tolower(c);
        printf("Char %c is %s\n", c, (isupper(c)) ? "big" : "small");
        
        cin.get();
}

#include <iostream>
#include <ctype.h>
using namespace std;
 
int main()
{
setlocale(0,"");
char *p;
int i;
char str[80] = "Сникерс Настоящий";
p = str;
for(i = 0; p[i]; i++) {
if(isupper(p[i]))
p[i] = tolower(p[i]);
else
if(islower(p[i]))
p[i] = toupper(p[i]);
}
 
 
cout<<"Результат\n"<<str;
cin.get();
}

#include <iostream>
#include <ctype.h>
 
using namespace std;
 
int main( void ) {
 
int i;
unsigned char buf[100];
 
 
setlocale( LC_ALL, "" );
 
strcpy( (char*)buf, "Сникерс Настоящий" );
for ( i= 0; buf[i]!='\0'; i++ ) {
    if ( isupper( buf[i] ) ) {
        buf[i]= tolower( buf[i] );
    } else if ( islower( buf[i] ) ) {
        buf[i]= toupper( buf[i] );
    }
}
 
cout <<"Result\n" <<buf <<"\n";
return 0;
 
}

strcpy( (char*)buf, "Сникерс Настоящий" );

(char*)buf