Make love tester in python:
while True:
sum = 0
name1 = input('name 1: ')
name2 = input('name 2: ')
for i in range(len(name1)):
sum += ord(name1[i])
for i in range(len(name2)):
sum += ord(name2[i])
match = 1 + (sum % 100)
print("love test result:")
print(match)
Write the same program in c++:
#include <iostream>
using namespace std;
int main()
{
while(1) {
string name1;
string name2;
cout << "name1: ";
cin >> name1;
cout << "name2: ";
cin >> name2;
int sum = 0;
for (int i = 0; i < name1.size(); i++) {
sum += name1[i];
}
for (int i = 0; i < name2.size(); i++) {
sum += name2[i];
}
int match = 1 + (sum % 100);
cout << "love test result:" << endl;
cout << match << endl;
}
}
cin is character input, you can perform a read operation by geting data out of cin with >>. Both cin and cout are streams. We will talk more about it later. For now just remember cin >> variable will read from the input and put the value in variable, and cout << variable will print the value of the variable.
rock paper scissors again
import random
options = ['rock','paper','scissors']
while True:
player = input(' '.join(options) + ': ')
if player not in options:
print("i dont know what to do with " + player)
continue
computer = random.choice(options)
print(computer)
if player == computer:
print("its a tie!")
if player == 'rock':
if computer == 'paper':
print('U lose the round')
elif computer == 'scissors':
print('U win this round')
if player == 'paper':
if computer == 'rock':
print('U win this round')
elif computer == 'scissors':
print('U lose the round')
if player == 'scissors':
if computer == 'rock':
print('U lose the round')
elif computer == 'paper':
print('U win this round')
sum things
data = ['hello','world','earth']
r = ''
for d in data:
r += d
print(r)
data = [1,2,3]
r = 0
for d in data:
r += d
print(r)
data = [[1,2],[3,4],[5,6]]
r = []
for d in data:
r += d
print(r)
The pattern, start with an empty result, iterate over the list and append append to the result is very very common. Examine the above code and notice how the part where it adds to the result is the same regardless if the list is list of strings, integers or list of lists
Back to basics, how are strings layed out in memory, and how many bytes the primitive types occupy in memory:
#include <iostream>
using namespace std;
int main(void) {
char c = 'a';
int x = 'a';
bool b = true;
int sum = 0;
long l = 1;
short s = 1;
float f = 0.555;
double d = 0.4123123;
long double ld = 0.123123;
cout << "char" << sizeof(c) << endl;
cout << "bool" << sizeof(b) << endl;
cout << "int" << sizeof(sum) << endl;
cout << "short" << sizeof(s) << endl;
cout << "long" << sizeof(l) << endl;
cout << "float" << sizeof(f) << endl;
cout << "double" << sizeof(d) << endl;
cout << "long double" << sizeof(ld) << endl;
int ages[10]= {10,12,10,9,10,12,12,2,3,2};
cout << sizeof(ages) << endl;;
long double z[5] = {0,0,0,0,0};
cout << sizeof(z) << endl;;
char s1[10] = {'h','e','l','l','o','w','o','r','d','\0'};
char s2[] = "helloword";
cout << s1 << endl;
cout << s2 << endl;
}
argc and argv
#include <iostream>
using namespace std;
int main(int argc, char* argv[]) {
cout << "Have " << argc << " arguments:" << endl;
cout << "my name is: " << argv[0] << endl;
for (int i = 0; i < argc; ++i) {
cout << i << ": " << argv[i] << endl;
}
return 0;
}
Compile the the program above as g++ -o xyz file.cpp, and run it with ./xyz hello world "aaa bbbb cccc" ddd. You see g++ has a main function as well, and it has argc and argv as well.
Formatting example:
#include <iostream>
#include <iomanip>
using namespace std;
int main(void) {
for (int fahr=0; fahr<=100; fahr+=10){
cout<< endl
<< setw(6)
<< setprecision(0)
<< fahr
<< setw(10)
<< setprecision(3)
<< 5.0/9.0 * (fahr-32.0);
}
cout << endl;
return(0);
}
c/c++ pointes and arrays are sometimes confusing, we will come back to them multiple times, especially because strings are pointers to arrays of characters, it is important for the concept to "click". Do not worry if you dont get it at first (or at second, or at third) attempt.
There are two important operators '*' and '&', int *pa = &a means we have a pointer (*) to a variable of type int equal to the address (&) of variable a. The value of pa is just a number, it is literally the address of the memory where the value of a will be.
The most important concept is that pa is actually just a number, this is the actual value of pa, and with *pa = 5 means, go to this place in memory and put 5 there, we can literally go anywhere in memory and put some value there.
Arrays are a continuous chunks of memory, char b[10] means b is a pointer to somewhere in memory where you hold 10 slots of type char which is 10 bytes. so b actually just holds the location of those 10 bytes. Thats right, b is a pointer, we can do b[2] = 'a' or *(b + 2) = 'a' they are the same thing, as b[2] means go to wherever b points to, and add 2 slots of b's type, same as *(b + 2).
Examine the following program:
#include <iostream>
using namespace std;
int main(int argc, char* argv[]) {
int a = 7;
int *pa = &a;
*pa = 8;
cout << a << endl;
int b[8] = {10,11,12,13,14,15,16,17};
cout << b << endl;
cout << (b + 3) << endl;
cout << *(b + 3) << endl;
cout << b[3] << endl;
return 0;
}
Tic tac toe with 9 variables, one for each position of the grid.
This is how the gameplay should look:
a b c
0 - - -
1 - - -
2 - - -
[x] enter position (row col): 0 a
a b c
0 x - -
1 - - -
2 - - -
[0] enter position (row col): 0 b
a b c
0 x 0 -
1 - - -
2 - - -
[x] enter position (row col): 1 a
a b c
0 x 0 -
1 x - -
2 - - -
[0] enter position (row col): 1 b
a b c
0 x 0 -
1 x 0 -
2 - - -
[x] enter position (row col): 2 a
a b c
0 x 0 -
1 x 0 -
2 x - -
x wins!
And this is the code:
#include <iostream>
using namespace std;
void render(char g0, char g1, char g2, char g3, char g4, char g5, char g6, char g7, char g8) {
cout << " a b c" << endl;
cout << "0 " << g0 << " " << g1 << " " << g2 << endl;
cout << "1 " << g3 << " " << g4 << " " << g5 << endl;
cout << "2 " << g6 << " " << g7 << " " << g8 << endl;
}
bool wins(char symbol, char g0, char g1, char g2, char g3, char g4, char g5, char g6, char g7, char g8) {
if (g0 == symbol && g1 == symbol && g2 == symbol) {
return true;
}
if (g0 == symbol && g3 == symbol && g6 == symbol) {
return true;
}
if (g0 == symbol && g4 == symbol && g8 == symbol) {
return true;
}
if (g1 == symbol && g4 == symbol && g7 == symbol) {
return true;
}
if (g2 == symbol && g5 == symbol && g8 == symbol) {
return true;
}
if (g3 == symbol && g4 == symbol && g5 == symbol) {
return true;
}
if (g6 == symbol && g7 == symbol && g8 == symbol) {
return true;
}
if (g6 == symbol && g4 == symbol && g2 == symbol) {
return true;
}
return false;
}
int main(void) {
char g0,g1,g2,g3,g4,g5,g6,g7,g8;
g0 = g1 = g2 = g3 = g4 = g5 = g6 = g7 = g8 = '-';
char symbol = 'x';
while(1) {
render(g0,g1,g2,g3,g4,g5,g6,g7,g8);
char row,col;
cout << "[" << symbol << "] enter position (row col): ";
cin >> row >> col;
cout << endl;
if (row == '0') {
if (col == 'a') {
g0 = symbol;
}
if (col == 'b') {
g1 = symbol;
}
if (col == 'c') {
g2 = symbol;
}
}
if (row == '1') {
if (col == 'a') {
g3 = symbol;
}
if (col == 'b') {
g4 = symbol;
}
if (col == 'c') {
g5 = symbol;
}
}
if (row == '2') {
if (col == 'a') {
g6 = symbol;
}
if (col == 'b') {
g7 = symbol;
}
if (col == 'c') {
g8 = symbol;
}
}
if (wins(symbol,g0,g1,g2,g3,g4,g5,g6,g7,g8)) {
render(g0,g1,g2,g3,g4,g5,g6,g7,g8);
cout << symbol << " wins!" << endl;
break;
}
if (symbol == 'x') {
symbol = '0';
} else {
symbol = 'x';
}
}
return 0;
}
Make Tic Tac Toe in python using 9 variables; Completely on your own.
(this is the code that she wrote)
def board(a1,a2,a3,b1,b2,b3,c1,c2,c3):
print(' ',1,2,3)
print('a ',a1,a2,a3)
print('b ',b1,b2,b3)
print('c ',c1,c2,c3)
def game():
a1 = '-'
a2 = '-'
a3 = '-'
b1 = '-'
b2 = '-'
b3 = '-'
c1 = '-'
c2 = '-'
c3 = '-'
xz = 'x'
while True:
board(a1,a2,a3,b1,b2,b3,c1,c2,c3)
ask = input(xz + ' choose a number from 1,2,3 and a letter from a,b,c: ')
if ask == 'a1':
a1 = xz
if ask == 'a2':
a2 = xz
if ask == 'a3':
a3 = xz
if ask == 'b1':
b1 = xz
if ask == 'b2':
b2 = xz
if ask == 'b3':
b3 = xz
if ask == 'c1':
c1 = xz
if ask == 'c2':
c2 = xz
if ask == 'c3':
c3 = xz
if a1 == xz and a2 == xz and a3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if a3 == xz and b3 == xz and c3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if a2 == xz and b2 == xz and c2 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if a1 == xz and b1 == xz and c1 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if c1 == xz and c2 == xz and c3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if b1 == xz and b2 == xz and b3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if c1 == xz and b2 == xz and a3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if a1 == xz and b2 == xz and c3 == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if xz == 'x':
xz = '0'
else:
xz = 'x'
game()
Another way to write the same program, using few function.
def print_board(a1,a2,a3,b1,b2,b3,c1,c2,c3):
print(' ',1,2,3)
print('a ',a1,a2,a3)
print('b ',b1,b2,b3)
print('c ',c1,c2,c3)
def win(xz, a1,a2,a3,b1,b2,b3,c1,c2,c3):
if a1 == xz and a2 == xz and a3 == xz:
return True
if a3 == xz and b3 == xz and c3 == xz:
return True
if a2 == xz and b2 == xz and c2 == xz:
return True
if a1 == xz and b1 == xz and c1 == xz:
return True
if c1 == xz and c2 == xz and c3 == xz:
return True
if b1 == xz and b2 == xz and b3 == xz:
return True
if c1 == xz and b2 == xz and a3 == xz:
return True
if a1 == xz and b2 == xz and c3 == xz:
return True
return False
def get_input(xz, a1,a2,a3,b1,b2,b3,c1,c2,c3):
ask = input(xz + ' choose a number from 1,2,3 and a letter from a,b,c: ')
if ask == 'a1':
a1 = xz
if ask == 'a2':
a2 = xz
if ask == 'a3':
a3 = xz
if ask == 'b1':
b1 = xz
if ask == 'b2':
b2 = xz
if ask == 'b3':
b3 = xz
if ask == 'c1':
c1 = xz
if ask == 'c2':
c2 = xz
if ask == 'c3':
c3 = xz
return a1,a2,a3,b1,b2,b3,c1,c2,c3
def game():
a1 = a2 = a3 = b1 = b2 = b3 = c1 = c2 = c3 = '-'
xz = 'x'
while True:
print_board(a1,a2,a3,b1,b2,b3,c1,c2,c3)
a1,a2,a3,b1,b2,b3,c1,c2,c3 = get_input(xz, a1,a2,a3,b1,b2,b3,c1,c2,c3)
if win(xz, a1,a2,a3,b1,b2,b3,c1,c2,c3):
print(xz + " WINS 🥳🥳🥳!!!")
break
if xz == 'x':
xz = '0'
else:
xz = 'x'
game()
Now the game loop is very obvious:
- print the board
- get the input and modify the variables
- check if there is a winnner
- swap the symbol (from x to 0 and from 0 to x)
But in the same time, when you read the functions it is a bit confusing what is a1 a2 a3.. etc. This is ok for such a small program, either way works fine, but when programs grow you have to think about 'wait if someone is reading this function, will it make sense', 'will my variable names make sense to someone else'.
Do the same tic tac toe but with a list instead of 9 variables
(this is the code that she wrote)
def board(g):
print(' ',1,2,3)
print('a ',g[0],g[1],g[2])
print('b ',g[3],g[4],g[5])
print('c ',g[6],g[7],g[8])
def game():
g = ['-','-','-','-','-','-','-','-','-']
xz = 'x'
while True:
board(g)
ask = input(xz + ' choose a number from 1,2,3 and a letter from a,b,c: ')
if ask == 'a1':
g[0] = xz
if ask == 'a2':
g[1] = xz
if ask == 'a3':
g[2] = xz
if ask == 'b1':
g[3] = xz
if ask == 'b2':
g[4] = xz
if ask == 'b3':
g[5] = xz
if ask == 'c1':
g[6] = xz
if ask == 'c2':
g[7] = xz
if ask == 'c3':
g[8] = xz
if g[0] == xz and g[1] == xz and g[2] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[3] == xz and g[4] == xz and g[5] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[6] == xz and g[7] == xz and g[8] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[1] == xz and g[4] == xz and g[7] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[0] == xz and g[3] == xz and g[6] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[2] == xz and g[5] == xz and g[8] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[0] == xz and g[4] == xz and g[8] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if g[2] == xz and g[4] == xz and g[6] == xz:
print(xz+ ' Wins 🥳🥳🥳')
break
if xz == 'x':
xz = '0'
else:
xz = 'x'
game()
alternative way of writing this:
def board(g):
print(' ',1,2,3)
print('a ',g[0],g[1],g[2])
print('b ',g[3],g[4],g[5])
print('c ',g[6],g[7],g[8])
def check(g, xz, i1,i2,i3):
if g[i1] == xz and g[i2] == xz and g[i3] == xz:
return True
return False
def game():
g = ['-','-','-','-','-','-','-','-','-']
xz = 'x'
while True:
# print the board
board(g)
# get the input and update the game board
ask = input(xz + ' choose a number from 1,2,3 and a letter from a,b,c: ')
index = 0
if ask[0] == 'a':
index = 0 + int(ask[1]) - 1 # convert a1 to index 0, a3 to index 3
if ask[0] == 'b':
index = 3 + int(ask[1]) - 1 # convert b1 to index 3 and b3 to index 5
if ask[0] == 'c':
index = 6 + int(ask[1]) - 1 # convert c1 to index 6 and c3 to index 8
g[index] = xz
# check if we have a winner
# horizontal
if check(g,xz,0,1,2) or check(g,xz,3,4,5) or check(g,xz,6,7,8):
print(xz+ ' Wins 🥳🥳🥳')
break
# vertical
if check(g,xz,1,4,7) or check(g,xz,0,3,6) or check(g,xz,2,5,8):
print(xz+ ' Wins 🥳🥳🥳')
break
# diagonal
if check(g,xz,0,4,8) or check(g,xz,2,4,6):
print(xz+ ' Wins 🥳🥳🥳')
break
# swap the synmbol for the next turn
if xz == 'x':
xz = '0'
else:
xz = 'x'
game()