What are decision control instruction?

Decision control instructions, also known as “decision instructions” or “control flow instructions,” are fundamental concepts in computer programming that define a category of instructions used to determine how a program is executed. These commands allow a program to decide based on specific conditions or criteria. They let a program select various pathways or actions based on evaluating specified conditions. The following are key decision-making instructions:

Conditional statements

In programming, conditional statements are used to make judgments. They let us run a block of code if a specific condition is true or a different block of code if the condition is false. Typical examples include:

  • The if-else statement: Execute a code of if block if the given condition is true; otherwise, execute the code of else block.

  • The switch statement: Provide multiple code paths based on an expression’s value

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Example code

Here is some example code for better understanding:

#include <iostream>
using namespace std;
int main() {
    int num = 10;
    
    //if-else statement
    cout<<"Example of if-else statement"<<endl;
    if (num > 5) {
        cout << "The number is greater than 5." << endl;
    }
    else{
      cout<<"The number is smaller than 5"<< endl;
    }
    //switch statement
    cout<<"\n \nExample of switch statement"<<endl;
     int choice = 2;
    switch (choice) {
        case 1:
            cout << "You chose option 1." << endl;
            break;
        case 2:
            cout << "You chose option 2." << endl;
            break;
        default:
            cout << "Invalid choice." << endl;
    }
    return 0;
}

Limitations of conditional statements

  • Complexity in nesting: Nested conditional statements might be difficult to interpret and manage. The amount of nested conditions increases code readability, making it difficult to troubleshoot and comprehend the reasoning.

  • Code duplication: Code duplication can occur when conditional blocks contain similar or redundant code within distinct branches. This complicates maintenance because modifications must be made in several places.

  • Maintenance challenges: Maintaining conditional statements becomes more difficult as the codebase increases. It may become difficult to keep track of all the conditions, potentially leading to problems or undesired behavior.

Loop control statements

Loop control statement control the flow of a program within loops. These are some of the examples of loop control statements:

  • for loops: Run a block of code to a specific number of times.

  • while loops: Execute a code block repeatedly while a particular condition is true.

  • do while loops: Run a code block at least once before repeating it while a condition is true.

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Example code

Here is some example code for better understanding:

#include <iostream>
using namespace std;
int main() {
  //for loop
  cout<<"Example of for loop: "<<endl;
    for (int i = 0; i < 5; i++) {
        cout << "Iteration " << i << endl;
    }
  
  //while loop
  cout<<"\n\nExample of while loop: "<<endl;
    int count = 0;
    while (count < 5) {
        cout << "Count: " << count << endl;
        count++;
    }
  //do-while loop
  cout<<"\n\nExample of do-while loop: "<<endl;
  count = 0;
    do {
        cout << "Count: " << count << endl;
        count++;
    } while (count < 5);
    return 0;
}

Limitations of loop control statements

  • Complexity in nested loops: Like nested conditional statements, nested loops can grow complex and difficult to read or maintain. As the degree of nesting increases, so does code readability, making it more difficult to understand and debug.

  • Limited use for certain situations: Some loop control statements may not be appropriate in all situations. Sometimes, the for loop may be less intuitive than the while loop, and vice versa.

  • Potential for infinite loops: Falsely built loops can result in infinite loops, which continue eternally. This could occur due to erroneous termination conditions or logic faults, resulting in system freezes or crashes.

Branching instructions

Branching instructions are used to alter the execution sequence. This includes the following:

  • Unconditional jumps: Transfer control directly to a given point in the program.

  • Conditional jumps: Control is transferred to another point in the program dependent on a condition. It includes statements like while and if.

Example code

Here is some example code for more understanding:

#include <iostream>
using namespace std;
int main() {
  //unconditional jump
  cout << "This is before the jump." << endl;
    goto jump_here;
    cout << "This is after the jump." << endl;
jump_here:
    cout << "This is where the jump takes you." << endl;
    
}

Limitations of branching instructions

  • Inflexibility in some situations: Branching may not be the best choice in certain situations. Branching, for example, may not scale well when dealing with extremely dynamic or constantly changing situations.

  • Difficulty in debugging: Identifying and resolving problems within nested or complex branches can be difficult. Understanding the program’s exact path based on conditions might require challenging debugging.

Function calls

Executing a certain function or subroutine is decided upon when using function calls. Functions are frequently invoked in response to specified conditions or input parameters.

Example code

#include <iostream>
using namespace std;
//function declaration
void greet() {
    cout << "Hello, World!" << endl;
}
int main() {
    // Function call
    greet();
    return 0;
}

Limitations of the function call

  • High coupling: Functions with numerous dependencies or strong coupling might increase module interdependence.

  • Function call overhead: In some languages, a slight performance cost might be associated with making function calls due to the overhead of managing the call stack.

  • Nested functions: Functions within functions (nested functions) might increase complexity and reduce readability.

These decision-control instructions are required to develop programs that respond to changing conditions, human interaction, and dynamic data. They enable programs to display various behaviors, make intelligent decisions, and do repetitive activities quickly. Decision control is fundamental in all programming languages and essential for developing complicated and responsive software.

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