Software Development Concepts: Top-Down, Cohesion, and More

Posted on Jan 4, 2025 in Computers

Software Development Concepts

Dynamic Memory Allocation (DMA)

#include <stdio.h>
#include <stdlib.h>

int main() {
    int N, i, *numbers, largest, smallest;

    printf("Enter the number of elements: ");
    scanf("%d", &N);

    numbers = (int *)malloc(N * sizeof(int));
    if (numbers == NULL) {
        printf("Memory allocation failed.\n");
        return 1;
    }

    printf("Enter %d numbers:\n", N);
    for (i = 0; i < N; i++) {
        scanf("%d", &numbers[i]);
    }

    largest = smallest = numbers[0];

    for (i = 1; i < N; i++) {
        if (numbers[i] > largest) largest = numbers[i];
        if (numbers[i] < smallest) smallest = numbers[i];
    }

    printf("Largest: %d\n", largest);
    printf("Smallest: %d\n", smallest);

    free(numbers);
    return 0;
}

File Handling

#include <stdio.h>

int main() {
    FILE *source, *destination;
    char ch;

    source = fopen("student.txt", "r");
    if (source == NULL) {
        printf("Error: Cannot open source file.\n");
        return 1;
    }

    destination = fopen("info.txt", "w");
    if (destination == NULL) {
        printf("Error: Cannot open destination file.\n");
        fclose(source);
        return 1;
    }

    while ((ch = fgetc(source)) != EOF) {
        fputc(ch, destination);
    }

    printf("File copied successfully.\n");

    fclose(source);
    fclose(destination);
    return 0;
}

Reverse Number

#include <stdio.h>

int main() {
    int num, reversed = 0, sum = 0, count = 0, digit;
    float avg;

    printf("Enter a number: ");
    scanf("%d", &num);

    int originalNum = num;

    while (num != 0) {
        digit = num % 10;
        reversed = reversed * 10 + digit;
        sum += digit;
        count++;
        num /= 10;
    }

    avg = (float)sum / count;

    printf("Reversed Number: %d\n", reversed);
    printf("Sum of digits: %d\n", sum);
    printf("Average of digits: %.2f\n", avg);

    return 0;
}

Call by Value

#include <stdio.h>

void swapByValue(int a, int b) {
    int temp = a;
    a = b;
    b = temp;
    printf("Inside swapByValue: a = %d, b = %d\n", a, b);
}

int main() {
    int x = 5, y = 10;

    printf("Before swapByValue: x = %d, y = %d\n", x, y);
    swapByValue(x, y);
    printf("After swapByValue: x = %d, y = %d\n", x, y);

    return 0;
}

Call by Reference

#include <stdio.h>

void swapByReference(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

int main() {
    int x = 5, y = 10;

    printf("Before swapByReference: x = %d, y = %d\n", x, y);
    swapByReference(&x, &y);
    printf("After swapByReference: x = %d, y = %d\n", x, y);

    return 0;
}