How to generate 4 random number and those 4 number sum must be 100

Question

我想得到4个不同的随机数，它们的总数必须是100（rN1 + rN2 + rN3 + rn4 = 100）

Answer 1

Just like this:

NSInteger r1, r2, r3, r4;
r1 = arc4random_uniform(96);
r2 = arc4random_uniform(97-r1);
r3 = arc4random_uniform(98-r1-r2);
r4 = 100-r1-r2-r3;

Answer 2

I think, this is the easiest way to do this:

1. Generate 3 random number between 1 to 100.

2. Calculate the sum

3. and generate 4th number as - Add the difference between calculated sum and 100.

Answer 3

BOOL flag = false;
    int r,r1,r2,r3;
    while (!flag) {
         r = arc4random_uniform(100);
         r1 = arc4random_uniform(100);
         r2 = arc4random_uniform(100);
         r3 = arc4random_uniform(100);
        if (r+r1+r2+r3 == 100) {
            flag = true;
        }

    }
    NSLog(@"%d    %d    %d    %d",r,r1,r2,r3);