C & C++ Exploratory Codes: Part-1

README.md

C & C++ Exploratory Codes: Part-1

These are some of my experimentation codes I made while trying to understand F-Army & Thotro Arduino Library for DWM1000 module. It might be useful for future references, I think.

bytes-to-value.cpp

/*
Run this on: https://www.onlinegdb.com/
*/

#include <iostream>
#include <cstring>

typedef uint8_t byte;

using namespace std;

void writeValueToBytes(byte data[], uint64_t val, uint8_t n);
uint64_t bytesAsValue(byte data[], uint8_t n);
double x = 100000.7;
double y = 200.5;


int main()
{
    byte report[] = {0,0,0,0};
    uint32_t pos = static_cast<uint32_t>(x);
    writeValueToBytes(&report[0], static_cast<uint32_t>(x*1000), 4);
    cout << pos << endl;
    cout<<"Hello World"<<endl;
    printf("\n");
    for(int i = 0; i < 4; i++){
        printf("%#X\n", report[i]);
    }
    
    double pos_x = static_cast<double>(bytesAsValue(&report[0], 4));
    cout<<"Pos_x: " << pos_x <<endl;
    return 0;
}

void writeValueToBytes(byte data[], uint64_t val, uint8_t n) {
	for(auto i = 0; i < n; i++) {
		data[i] = ((val >> (i*8)) & 0xFF);
	}
}

uint64_t bytesAsValue(byte data[], uint8_t n) {
	uint64_t value = 0;
	for(auto i = 0; i < n; i++) {	
		value |= ((uint64_t)data[i] << (i*8));
	}
	return value;
}

check-equivalent.c

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

int check(int a, int b) {
    return a == b;
}

int main()
{
    int top = 1;
    int cap = 1;
    int nil = 0;
    
    int res1 = check(top, cap);
    int res2 = check(top, nil);
    
    printf("Res1: %d\n", res1);
    printf("Res2: %d\n", res2);
    
    return 0;
    
}

learn-pointer.c

#include <stdio.h>

int main()
{
    int *ptr, p;
    
    p = 22;
    printf("Address of p: %p\n", &p);
    printf("Value of p: %d\n\n", p);  // 22
    
    ptr = &p; // pointer to address of p
    printf("Address of pointer ptr: %p\n", ptr);
    printf("Content of pointer ptr: %d\n\n", *(ptr)); // 22
    
    *ptr = 3;
    
    printf("Address of p: %p\n", &p);
    printf("Value of p: %d\n\n", p);  // 22
    
    return 0;
}

learn-struct.c

/******************************************************************************
Welcome to GDB Online.
*******************************************************************************/
#include <stdio.h>


typedef struct Complex {
    int imag;
    float real;
} Complex;

typedef struct Number{
    Complex comp;
    int integers;
} Number;

int main()
{
    Number number, num_array[3];
    
    number.comp.imag = 11;
    number.comp.real = 10.5;
    number.integers = 12;
    
    printf("Imaginary number: %d\n", number.comp.imag);
    printf("Real number: %.2f\n", number.comp.real);
    printf("Integers: %d\n\n", number.integers);
    
    for(int i=0; i < 3; i++){
        num_array[i].comp.imag = i+1;
        num_array[i].comp.real = (float)(i+1.5);
        num_array[i].integers = i+3;
        
        printf("Imaginary number: %d\n", num_array[i].comp.imag);
        printf("Real number: %.2f\n", num_array[i].comp.real);
        printf("Integers: %d\n\n", num_array[i].integers);
    }

    return 0;
}

memory-allocation.c

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

int main()
{
    int n, i, *ptr, sum = 0;
    
    printf("Enter number of elements: ");
    scanf("%d", &n);
    
    ptr = (int*)malloc(n * sizeof(int));
    
    // if memory cannot be allocated
    if(ptr == NULL){
        printf("Error! Memory not allocated");
        exit(0);
    }
    
    printf("Enter elements: ");
    for(i = 0; i < n; i++){
        scanf("%d", ptr + i);
        sum += *(ptr + 1);
    }
    
    printf("Sum = %d", sum);
    
    // deallocating free Memory
    free(ptr);

    return 0;
}