Java Controls & Flow – Quick Reference

1. Conditional Statements

Statement	Syntax	Example
if	if (condition) { ... }	if (x > 0) { System.out.println("Positive"); }
if-else	if (condition) { ... } else { ... }	if (x > 0) { ... } else { ... }
if-else-if	if (...) {...} else if (...) {...} else {...}	if (score >= 90) { ... } else if (score >= 75) { ... } else { ... }
nested if	if (...) { if (...) {...} }	if (x>0){ if(x%2==0){...} }
switch	switch(var){ case val: ...; break; default: ...; }	switch(day){ case 1: ... break; default: ... }

---

2. Loops

Loop	Syntax	Example
for	for(init; condition; update){...}	for(int i=1;i<=5;i++){...}
while	while(condition){...}	while(i<=5){ i++; }
do-while	do{...} while(condition);	do{ i++; } while(i<=5);
for-each	for(type var : array/collection){...}	for(int n: numbers){...}

---

3. Jump Statements

Statement	Use
break	Exit loop or switch immediately
continue	Skip current iteration, continue next
return	Exit method immediately

---

4. Ternary Operator

Syntax	Example
condition ? valueIfTrue : valueIfFalse	String res = (x%2==0) ? "Even" : "Odd";

---

5. Flow Control Tips

• Always use {} for clarity.
• Avoid deep nesting; break into methods.
• Use switch for discrete values.
• Use for-each for collections when index not needed.
• Name variables clearly for readability.

---

6. Quick Visual Example

for (int n : numbers) {
    if (n > 0) {
        System.out.println("Positive");
    } else if (n < 0) {
        System.out.println("Negative");
    } else {
        System.out.println("Zero");
    }
}

---

✅ Memory Hooks:

• if → condition check
• switch → multi-choice
• for / while / do-while → loops
• break / continue / return → jump control
• ?: → quick if-else

---