C Control Flow

Quick Reference

Control structures:

// if-else
if (condition) { ... }
else if (other) { ... }
else { ... }

// switch
switch (x) {
    case 1:  /* ... */ break;
    case 2:  /* ... */ break;
    default: /* ... */ break;
}

// loops
for (int i = 0; i < n; i++) { ... }
while (condition) { ... }
do { ... } while (condition);

Common Pitfalls

• = vs == – Assignment in conditions is a logic bomb. Some use if (0 == x) to catch it.
• Missing break – Fall-through in switch is silent. Always add break unless intentional.
• Off-by-one – i <= n vs i < n is the source of countless bugs. Think about boundaries.
• Infinite loops – Forgetting to update the loop variable. Always check your exit condition changes.
• Dangling else – if (a) if (b) x; else y; – the else binds to the inner if. Use braces.