C++ Flow Control

Concept of Flow Control.

Flow of Control

In C++, flow control structures are used to dictate the order in which statements are executed in a program. The primary flow control structures in C++ include:

1. Sequential Execution:

In C++, statements are executed in the order they appear, from top to bottom.

#include <iostream>

int main() {
    std::cout << "Statement 1" << std::endl;
    std::cout << "Statement 2" << std::endl;
    std::cout << "Statement 3" << std::endl;

    return 0;
}

2. Selection Statements:

These statements allow the program to make decisions and execute different blocks of code based on certain conditions.

a. if Statement:

The 'if' statement is used for conditional execution.

if (condition) {
    // code to be executed if the condition is true
} else {
    // code to be executed if the condition is false
}

b. switch Statement:

The 'switch' statement allows for multi-way branching based on the value of an expression.

switch (expression) {
    case value1:
        // code to be executed if expression == value1
        break;
    case value2:
        // code to be executed if expression == value2
        break;
    // ...
    default:
        // code to be executed if expression doesn't match any case
}

3. Repetition Statements (Loops):

These statements allow a block of code to be repeated multiple times.

a. for Loop:

The 'for' loop is used when the number of iterations is known beforehand.

for (initialization; condition; update) {
    // code to be repeated
}

b. while Loop:

The 'while' loop is used when the number of iterations is not known beforehand.

while (condition) {
    // code to be repeated
}

c. do-while Loop:

The 'do-while' loop is similar to the while loop, but it guarantees that the loop body is executed at least once.

do {
    // code to be repeated
} while (condition);

4. Jump Statements:

These statements alter the normal flow of a program.

a. break Statement:

The 'break' statement is used to exit from a loop or a switch statement.

for (int i = 0; i < 10; ++i) {
    if (i == 5) {
        break; // Exit the loop when i is 5
    }
    std::cout << "Iteration " << i << std::endl;
}

b. continue Statement:

The 'continue' statement skips the rest of the loop body and continues with the next iteration.

for (int i = 0; i < 5; ++i) {
    if (i == 2) {
        continue; // Skip iteration when i is 2
    }
    std::cout << "Iteration " << i << std::endl;
}

c. return Statement:

The 'return' statement is used to exit from a function.

int square(int x) {
    return x * x;
}

d. goto Statement (not recommended):

The 'goto' statement allows jumping to a labeled statement. However, using this statement is generally discouraged due to its impact on code readability and maintainability.

int main() {
    int x = 0;

    if (x == 0) {
        goto exit;
    }

    // Code that should not be executed if x == 0

    exit:
    return 0;
}

* Understanding these flow control structures and their appropriate use is essential for writing efficient and maintainable C++ code.

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