c / c-control-flow
15 mins
C Level 2: Branching & Loop Iteration
Why This Matters: Control structures allow programs to make decisions and repeat execution blocks efficiently.
## Branching & Loop Mechanics Program flow determines which statements execute based on boolean conditions. ### Loop Constructs - `for(init; condition; update)`: Best for known iteration counts. - `while(condition)`: Pre-condition check iteration. - `do ... while(condition)`: Guarantees at least 1 execution pass.
MENTAL MODEL & MEMORY LAYOUT
[ Loop Start ] ──► [ Check Condition ] ──(True)──► [ Execute Block ]
│ │
(False) │
▼ ▼
[ Exit Loop ] ◄─────────────────[ Update ] COMMON PITFALLS TO AVOID
- Infinite loop caused by forgetting loop index increment (i++).
- Off-by-one errors (using `<` when `<=` is required).
For Loop Accumulator
#include <stdio.h>
int main() {
int sum = 0;
for(int i = 1; i <= 5; i++) {
sum += i;
}
printf("Sum 1..5: %d\n", sum);
return 0;
}Iterates i from 1 to 5, accumulating total sum.
CONCEPT MASTERY CHECKPOINT
Which loop construct guarantees the body will execute AT LEAST ONCE?
NEXT RECOMMENDED LESSON
C Level 3: Functions & Scope
Challenge: Write a for loop in C that computes and prints the sum of numbers from 1 to 5.