Question

For my computer programming class, I decided to make a program that generates a random coin flip and keeps track of the longest consecutive streak for both heads and tails. I have searched the internet and found no answer. The count is not displaying right. Even just a hint would be great!
Thanks,
Justin

int main(){

    int number_of_flips;
    int coin_flip;
    int previous_flip = 2;
    int head_count = 0;
    int tail_count = 0;
    int highest_head = 0;
    int highest_tail = 0;

    srand(time(NULL));

    cout << "Enter the number of coin flips:" << endl;
    cin >> number_of_flips;
    system("cls");

    for(int i = 0; i < number_of_flips; i++){


        coin_flip = rand() % 2;

        if(coin_flip == 0){
            cout << "Heads" << endl;
            if(coin_flip == previous_flip){
                  head_count = head_count + 1;       
             }
             else{
                 if(head_count > highest_head){
                     highest_head = head_count;                  
                 }

                 head_count = 0;      
             }
        }

        if(coin_flip == 1){
            cout << "Tails" << endl;
            if(coin_flip == previous_flip){
                  tail_count = tail_count + 1;        
            }
            else{
                 if(tail_count > highest_tail){
                      highest_tail = tail_count;              
                 }

                 tail_count = 0;     
            }
        }


        previous_flip = coin_flip;
    }

    cout << "The longest run of heads is " << highest_head << endl;
    cout << "The longest run of tails is " << highest_tail << endl;

    system("pause");
    return 0;
}

Here is an example of the output:

Tails
Tails
Tails
Heads
Heads
Tails
Tails
Tails
Tails
Heads
The longest run of heads is 1
The longest run of tails is 2

As a reference, here is my final code that I believe works now:

int main(){

    int number_of_flips;
    int coin_flip;
    int previous_flip = 2;
    int head_count = 0;
    int tail_count = 0;
    int highest_head = 0;
    int highest_tail = 0;

    srand(time(NULL));

    cout << "Enter the number of coin flips:" << endl;
    cin >> number_of_flips;
    system("cls");

    for(int i = 0; i < number_of_flips; i++){


        coin_flip = rand() % 2;

        if(coin_flip == 0){
            cout << "Heads" << endl;
            if(coin_flip == previous_flip){
                  head_count = head_count + 1;       
             }
             else{
                 if(head_count > highest_head){
                     highest_head = head_count;                  
                 }

                 head_count = 1;      
             }
        }

        if(coin_flip == 1){
            cout << "Tails" << endl;
            if(coin_flip == previous_flip){
                  tail_count = tail_count + 1;        
            }
            else{
                 if(tail_count > highest_tail){
                      highest_tail = tail_count;              
                 }

                 tail_count = 1;     
            }
        }
        previous_flip = coin_flip;
    }
    if(head_count > highest_head){
           highest_head = head_count;              
    }
    if(tail_count > highest_tail){
           highest_tail = tail_count;              
    }
    cout << "The longest run of heads is " << highest_head << endl;
    cout << "The longest run of tails is " << highest_tail << endl;

    system("pause");
    return 0;
}

Answer 1

Your code doesn’t take into account the last streak, because you only check against highest_head or highest_tail when the next flip is different. On the last flip, there is no next flip.

Since this is homework, I’ll refrain from suggesting how to fix your code.