Paper A: Dec 2025 / Jan 2026 (Solved)

Analysis of the APJ Abdul Kalam Technological University B.Tech Degree S2 (S) / S1 (Challenge Course) Examination questions.

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Part A (Selected Logic)

1. Expression Evaluation

Question: Calculate and print the result of: 8 + 3 * (10 - 6) / 2 Solution:

• 10 - 6 = 4
• 3 * 4 = 12
• 12 / 2 = 6
• 8 + 6 = 14 Output: 14

2. String Length without Built-ins

Implementation:

int length = 0;
while(str[length] != '\0') length++;

3. Storage Classes IDENTIFIED

Trace:

int x; // Extern (Global)
int main() {
    int y; // Auto (Local)
}

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Part B (Program Implementation)

Q9a. Perfect Number

Checks if the sum of divisors equals the number.

int isPerfect(int n) {
    int sum = 0;
    for(int i = 1; i <= n/2; i++) {
        if(n % i == 0) sum += i;
    }
    return (sum == n);
}

Q10a/11a. Digit Frequency & Matrix Symmetry

• Digit Frequency: Using an array of size 10 to count occurrences of 0-9.
• Symmetry: Verifying A[i][j] == A[j][i] for a square matrix.

Q13b. Decimal to Binary

Iterative approach using modulo and division.

void decToBin(int n) {
    int bin[32], i = 0;
    while(n > 0) { 
        bin[i++] = n % 2; 
        n /= 2; 
    }
    for(int j = i-1; j >= 0; j--) printf("%d", bin[j]);
}

Q16b. Time Structure Arithmetic

Adding two time values and handling minute overflow (> 60).

void addTime(struct Time t1, struct Time t2, struct Time *res) {
    res->m = (t1.m + t2.m) % 60;
    res->h = t1.h + t2.h + ((t1.m + t2.m) / 60);
}