Course source code: https://codistwa.com/guides/loops. More courses on https://codistwa.com

loops.c

// ============================================================
// Simple for loop
// ============================================================

int fruits [3] = {1, 2, 3};

for (int i = 0; i < 3; i++)
  printf("%d\n", fruits[i] * 2);

// ============================================================
// parameters
// ============================================================

int fruits [3] = {1, 2, 3};

for (int i = 1; i < 3; i++)
  printf("%d\n", fruits[i] * 2);

// ============================================================
// decrementation
// ============================================================

int fruits [5] = {1, 2, 3, 4, 5};

for (int i = 5; i >= 2; i--)
  printf("%d\n", i);

// ============================================================
// nested
// ============================================================

int cars[5] = { 1, 2, 3, 4, 5 };

for (int i = 0; i < 5; i++) {
  for (int j = 0; j < i; j++) {
      printf ("%d %d\n", i, j);
  }
  printf ("");
}

// ============================================================
// While
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;

while (i < 3) {
  printf ("%d\n", fruits[i] * 2);
  i++;
}

// ============================================================
// Do while
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;

do {
   printf ("%d\n", fruits[i] * 2);
   i++;
}
while (i < 3);

// ============================================================
// Break
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;
while (1 < 3) {
  i++;
  if (i == 2)
  break;
}
printf ("%d\n", i);

loops.cpp

// ============================================================
// Simple for loop
// ============================================================

int fruits [3] = {1, 2, 3};
    
for (int i = 0; i < 3; i++)
  cout << fruits[i] * 2 << endl;

// ============================================================
// parameters
// ============================================================

int fruits [3] = {1, 2, 3};
    
for (int i = 1; i < 3; i++)
  cout << fruits[i] * 2 << endl;

// ============================================================
// decrementation
// ============================================================

int fruits [5] = {1, 2, 3, 4, 5};
    
for (int i = 5; i >= 2; i--)
  cout << i << endl;

// ============================================================
// nested
// ============================================================

int cars[5] = { 1, 2, 3, 4, 5 };

for (int i = 0; i < 5; i++) {
   for (int j = 0; j < i; j++) {
      cout << i << " " << j << endl;
   }
  cout << "" << endl;
}

// ============================================================
// While
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;

while (i < 3) {
   cout << fruits[i] * 2 << endl;
   i++;
}

// ============================================================
// Do while
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;

do {
      cout << fruits[i] * 2 << endl;
      i++;
}
while (i < 3);

// ============================================================
// Break
// ============================================================

int fruits[3] = { 1, 2, 3 };
int i = 0;
while (1 < 3) {
  i++;
  if (i == 2)
  break;
}
cout << i << endl;

loops.js

// ============================================================
// Simple for loop
// ============================================================

const fruits = [1, 2, 3];

for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i] * 2);
}

// ============================================================
// parameters
// ============================================================

const fruits = [1, 2, 3];

for (let i = 1; i < fruits.length; i++) {
   console.log(fruits[i] * 2);
}

// ============================================================
// decrementation
// ============================================================

const fruits = [1, 2, 3, 4, 5];

for (let i = fruits.length; i >= 2; i--) {
  console.log(i); // 5 4 3 2
}

// ============================================================
// nested
// ============================================================

const cars = [1, 2, 3, 4, 5];

for (let i = 0; i < cars.length; i++) {
  for (let j = 0; j < i; j++) {
    console.log(i, j);
  }
  console.log('');
}

// ============================================================
// While
// ============================================================

const fruits = [1, 2, 3];
let i = 0;

while (i < fruits.length) {
  console.log(fruits[i] * 2);
  i++;
}

// ============================================================
// Do while
// ============================================================

const fruits = [1, 2, 3];
let i = 0;

do {
  console.log(fruits[i] * 2);
  i++;
} 
while (i < fruits.length);

// ============================================================
// Break
// ============================================================

const fruits = [1, 2, 3];
let i = 0;
while (i < fruits.length) {
  i++;
  if (i === 2) {
    break;
  }
}

console.log(i);

loops.py

# ============================================================
# Simple for loop
# ============================================================

fruits = [1, 2, 3]

for x in fruits:
  print(x * 2)

# ============================================================
# nested
# ============================================================

cars = [1, 2, 3, 4, 5]

for i in cars:
    for j in cars:
        print(i, j)
    print('')

# ============================================================
# While
# ============================================================

fruits = [1, 2, 3]
i = 0

while i < len(fruits):
  print(fruits[i] * 2)
  i += 1

# ============================================================
# Break
# ============================================================

fruits = [1, 2, 3]
i = 0

while i < len(fruits):
    if i == 2:
        break
    i += 1
print(i)