the rand() function and strings

[johnmerlino]

I am looking at this piece of code:

#include <iostream>
#include <string>
#include <cstdlib> // for rand() and srand()
#include <ctime> // for time()
 
using namespace std;
 
int main()
{
    srand(time(0)); // seed random number generator
 
    string sString; // length 0
    sString.reserve(64); // reserve 64 characters
 
    // Fill string up with random lower case characters
    for (int nCount=0; nCount < 64; ++nCount)
        sString += 'a' + rand() % 26;
 
    cout << sString;
}

I'm confused about this part right here:
'a' + rand() % 26

The rand() function returns an integral number in the range between 0 and RAND_MAX. I assume RAND_MAX here is 26. And this is randomly return one of the 26 letters of the alphabet. But what is the point of the 'a' here?

[xismn]

If I want a random number between 5 and 10, then that means that 5 is the minimum, and 10 the maximum.

Therefore:
5 + (rand()%10)

In ascii, 'a' is 97 in decimal.
The purpose of the 'a' in this case, is to create a random number and then add 'a'(97), the minimum, to it. Otherwise, you'd be creating characters from 0-25

[LB]

@xismn your formula will never generate the number 10.

[giblit]

To generate a random number in a range the formula is:
rand() % ( max - min + 1 ) + min;

[xismn]

Seriously, I'm on a roll today. Let's just pretend I said "exclusive"...