Index
Loops
Loops are fundamental constructs in programming that allow you to execute a block of code repeatedly based on a specified condition. In C++, there are several types of loops:
1. While Loop:
Executes a block of code repeatedly as long as a specified condition is true.
while (condition) {
// Code to be executed
}
Example:
#include <iostream>
using namespace std;
int main() {
int i = 0;
while (i < 4) {
cout << i << "\n";
i++;
}
return 0;
}
Output:
0
1
2
3
2. Do-While Loop:
Similar to the while loop, but it guarantees that the block of code is executed at least once before checking the condition.
do {
// Code to be executed
} while (condition);
Example:
#include <iostream>
using namespace std;
int main() {
int i = 0;
do {
cout << i << "\n";
i++;
}
while (i < 4);
return 0;
}
Output:
0
1
2
3
3. for Loop:
Executes a block of code a specified number of times, typically based on an initialization, condition, and update statement.
for (initialization; condition; update) {
// Code to be executed
}
Example:
#include <iostream>
using namespace std;
int main() {
for (int i = 0; i < 4; i++) {
cout << i << "\n";
}
return 0;
}
Output:
0
1
2
3
4.Nested Loop:
A nested loop in programming refers to placing one loop inside another loop. This enables you to iterate over elements in a multidimensional data structure, such as a two-dimensional array, or to perform repetitive tasks with multiple levels of iteration.
Example:
#include <iostream>
using namespace std;
int main() {
// Outer loop
for (int i = 1; i <= 3; ++i) {
cout << "Outer: " << i << "\n"; // Executes 2 times
// Inner loop
for (int j = 1; j <= 2; ++j) {
cout << " Inner: " << j << "\n"; // Executes 6 times (2 * 3)
}
}
return 0;
}
Output:
Outer: 1
Inner: 1
Inner: 2
Outer: 2
Inner: 1
Inner: 2
Outer: 3
Inner: 1
Inner: 2
5. Foreach Loop:
In C++, the range-based for loop, also known as the “for each” loop, provides a concise way to iterate over elements in a container or a range. It’s particularly useful for iterating over the elements of an array, a standard library container such as a vector, list, or set, or any other data structure that supports iteration.
for (type variableName : arrayName) {
// code block to be executed
}
Example:
#include <iostream>
using namespace std;
int main() {
int myNumbers[5] = {1, 2, 3, 4, 5};
for (int i : myNumbers) {
cout << i << "\n";
}
return 0;
}
Ouput:
1
2
3
4
5
