c 2b 2b convert lowercase to uppercase

1for(int i=0;i<str.size();i++){
2int c = str[i]; 
3        if (islower(c))  
4            str[i] = toupper(c);
5}

1transform(str.begin(), str.end(), str.begin(), ::toupper); 

1#include<bits/stdc++.h> 
2using namespace std; 
3  
4int main() 
5{ 
6    string s = "Viet Nam"; 
7    transform(s.begin(), s.end(), s.begin(), ::toupper);  //uppercase
8    cout << s << endl; 
9    return 0; 
10}
11

1/* toupper example */
2#include <stdio.h>
3#include <ctype.h>
4int main ()
5{
6  int i=0;
7  char str[]="Test String.\n";
8  char c;
9  while (str[i])
10  {
11    c=str[i];
12    putchar (toupper(c));
13    i++;
14  }
15  return 0;
16}

1int i = 0;
2    while(str[i])
3    {
4        if(str[i] == std::toupper(str[i]) && std::isalpha(str[i]) == 1024)
5        str[i]+= 32;
6        ++i;
7    }