Three Control Structures in C Programming: Sequential, Selection, and Repetition

In C programming, control structures dictate the flow of execution of the program. There are three main types of control structures: sequential, selection, and repetition. Understanding and effectively using these control structures are essential for creating robust and efficient programs.

1. Sequential Control Structure

The sequential control structure is the default mode of execution in C where statements are executed one after another in the order they appear in the code. This is the simplest and most straightforward control structure.

Example

The following code snippet demonstrates a simple example of the sequential control structure.

include stdio.h
int main() {
    int a  5;
    int b  10;
    int sum  a   b;
    printf(The sum is: %d
, sum);
    return 0;
}

The program first declares and initializes the variables a and b. Then, it calculates the sum of these variables and prints the result to the console.

Flowchart

A flowchart for the sequential structure can be visualized as follows:

Start Declare and initialize variables a and b Calculate sum sum a b Print sum End

2. Selection Control Structure

Selection control structures allow the program to choose different paths of execution based on conditions. The most common selection structures in C are if, else if, and switch.

Example

The following example uses an if, else if, and else structure to determine whether a number is positive, negative, or zero.

include stdio.h
int main() {
    int number  15;
    if (number > 0) {
        printf(The number is positive.
);
    } else if (number 

In this example, the program checks the value of the variable number and prints a corresponding message based on the condition.

Flowchart

A flowchart for the selection structure can be visualized as follows:

Start Is number 0? Yes: Print The number is positive. No: Is number 0? Yes: Print The number is negative. No: Print The number is zero. End

3. Repetition Control Structure

Repetition control structures allow a block of code to be executed repeatedly based on a condition. The most common repetition structures in C are for, while, and do while.

Example

The following example uses a for loop to print numbers from 1 to 5.

include stdio.h
int main() {
    int i;
    for (i  1; i  5; i  ) {
        printf(%d
, i);
    }
    return 0;
}

In this example, the program uses a for loop to initialize, conditionally continue, and increment the loop counter i. It prints each value of i from 1 to 5.

Flowchart

A flowchart for the repetition structure can be visualized as follows:

Start Initialize i 1 Is i 5? Yes: Print i Increment i No: End End

These control structures form the backbone of decision-making and looping in C programming, allowing developers to create complex logic and functionality in their applications.