Flow Control in Programming: Making Decisions and Repeating Actions

When writing programs, you don’t just want the computer to run code line by line blindly—you want it to make decisions, repeat tasks, and react to conditions. This is where flow control comes in.

Flow control lets your program choose different paths or repeat blocks of code based on logic and conditions.


Key Flow Control Structures

1. Conditional Statements (Decision Making)

These let your program choose which code to run based on conditions.

  • if statement

java
if (score > 60) {
System.out.println("You passed!");
}
  • if-else statement

java
if (score > 60) {
System.out.println("You passed!");
} else {
System.out.println("You failed.");
}
  • if-else if-else ladder

java
if (score >= 90) {
System.out.println("Grade A");
} else if (score >= 75) {
System.out.println("Grade B");
} else {
System.out.println("Grade C");
}

2. Switch Statement

A cleaner way to select from many options:

java
switch (day) {
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
default:
System.out.println("Weekend");
}

3. Loops (Repetition)

Loops allow you to repeat code blocks multiple times.

  • for loop

java
for (int i = 0; i < 5; i++) {
System.out.println("Count: " + i);
}
  • while loop

java
int i = 0;
while (i < 5) {
System.out.println("Count: " + i);
i++;
}
  • do-while loop

java
int i = 0;
do {
System.out.println("Count: " + i);
i++;
} while (i < 5);

4. Control Flow Keywords

  • break: Exits a loop or switch statement immediately.

  • continue: Skips the current iteration and moves to the next loop cycle.

  • return: Exits from a method and optionally returns a value.


Why Flow Control Matters

Flow control gives your programs intelligence and flexibility, allowing you to:

  • Perform different actions based on user input or data.

  • Automate repetitive tasks efficiently.

  • Build complex logic and interactive applications.


Summary

Structure Purpose Example
if/else Conditional execution if (x > 0) {...} else {...}
switch Multi-way selection switch(day) {...}
for loop Repeat fixed times for(int i=0; i<5; i++) {...}
while loop Repeat while condition true while(condition) {...}
do-while loop Repeat at least once do {...} while(condition);

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