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Introduction to C++ For Loop
Basic Structure of For Loop:
A for loop in C++ is used to execute a block of code repeatedly for a specified number of times. The basic syntax includes initialization, condition, and increment/decrement.
int main() {
for (int i = 0; i < 5; i++) {
cout << i << " ";
}
return 0;
}
Console Output:
0 1 2 3 4
Nested For Loop
Understanding Nested Loops:
Nested loops are loops within loops. The inner loop will be executed one time for each iteration of the outer loop.
int main() {
for (int i = 1; i <= 3; i++) {
for (int j = 1; j <= 3; j++) {
cout << i << "," << j << " ";
}
cout << endl;
}
return 0;
}
Console Output:
1,1 1,2 1,3 2,1 2,2 2,3 3,1 3,2 3,3
For Loop with Arrays
Iterating Over Arrays:
For loops are commonly used to iterate over arrays, allowing you to perform operations on each element.
int main() {
int arr[] = {10, 20, 30, 40, 50};
for (int i = 0; i < 5; i++) {
cout << arr[i] << " ";
}
return 0;
}
Console Output:
10 20 30 40 50
Reverse Counting
Counting Backwards:
For loops can also be used to count backwards by using the decrement operator.
int main() {
for (int i = 5; i > 0; i--) {
cout << i << " ";
}
return 0;
}
Console Output:
5 4 3 2 1
Skipping Iterations
Using Continue Statement:
The continue statement can be used within a for loop to skip the current iteration and move to the next one.
int main() {
for (int i = 0; i < 5; i++) {
if (i == 2) continue;
cout << i << " ";
}
return 0;
}
Console Output:
0 1 3 4
Breaking Out of a Loop
Using Break Statement:
The break statement is used to exit a loop prematurely before the loop condition is false.
int main() {
for (int i = 0; i < 5; i++) {
if (i == 3) break;
cout << i << " ";
}
return 0;
}
Console Output:
0 1 2
For Loop with Step Value
Incrementing by Step:
You can control the increment of the loop variable by specifying a step value in the increment section.
int main() {
for (int i = 0; i < 10; i += 2) {
cout << i << " ";
}
return 0;
}
Console Output:
0 2 4 6 8
For Loop with Multiple Variables
Using Multiple Variables:
C++ allows you to initialize and use multiple variables in a for loop, separated by commas.
int main() {
for (int i = 0, j = 10; i < j; i++, j--) {
cout << i << "," << j << " ";
}
return 0;
}
Console Output:
0,10 1,9 2,8 3,7 4,6
Infinite For Loop
Creating Infinite Loops:
An infinite loop runs indefinitely, usually due to a missing condition or a condition that never evaluates to false.
int main() {
for (;;) {
cout << "Infinite Loop";
}
return 0;
}
Console Output:
Infinite Loop Infinite Loop Infinite Loop...
For Loop with Conditional Statements
Combining Conditional Logic:
You can use conditional statements within a for loop to execute different blocks of code based on certain conditions.
int main() {
for (int i = 0; i < 10; i++) {
if (i % 2 == 0) {
cout << i << " is even ";
} else {
cout << i << " is odd ";
}
}
return 0;
}
Console Output:
0 is even 1 is odd 2 is even 3 is odd 4 is even 5 is odd 6 is even 7 is odd 8 is even 9 is odd
