C/C++ Programming Overview

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char carray[23];
// char carray2[4] = a;
long long po [8];
po[0] = 1;
po[7] = po[0];
// po[8];

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int a = 10, b = 1;
int* aptr = NULL;
// double * dptr = &a;
aptr = &a; // aptr -> a, a = 10, b = 1
*aptr = b; // aptr -> a, a = 1, b = 1
a = 2; // aptr -> a, a = 2, b = 1
b = 7; // aptr -> a, a = 2, b = 7
&a = b; // aptr -> old a, old a = 2, b(a) = 7;
printf("%d %d", a, *aptr); // 7 2

int * potato = NULL;
if(potato == NULL)
    printf("hi");

potato = (int *)malloc(sizeof(int) * 127);

if(potato == NULL)
    printf("Memory allocation failed.\n");

potato = NULL;
if(potato != NULL)
    free(potato);

potato[4] = 4; // *(potato + 4) = 4;

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if(1)
{
    printf("Potato");
}
else
{
    printf("P04A40");
}

int a = 0;
if(a++)
{
    printf("Smashed potato.");
}

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int a = 32, b = 0;

switch (a) {
    case 32:
        printf("32 potatos");
    case 0:
        printf("Void");
        break;
    default:
        printf("Frog");
}

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int i = 1;
for(i -= 1; i <= INT_MAX; i++)
{
    printf("%d", i);
}

float a[10];
float * b = (float *)malloc(sizeof(float) * 10);
float* a_end = a + 10;

for(float* a_ptr = a; a < a_end; a++)
    printf("%f ", *a_ptr);

// deferences between array and pointer
// C++ only
for(auto x : a)
    printf("%f ", x);
/*
for(auto x : b)
    printf("%f ", x);
*/

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while(True)
{}

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int x = 10;
while(x--)
{}

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

int potato(int frog)
{
    int potato2;
    frog = 11;
    return 0;
}

int main()
{
    int frog = 1;
    int potato2;
    potato(frog);
    printf("%d\n", frog);
    return 0;
}

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

int potato()
{
    // int frog = 11;
    // return frog;
    return 11;
}

void potato2(int * frog1, int * frog2)
{
    *frog1 = 11;
    *frog2 = 12;
    return;
}

int main()
{
    int frog = 1;
    frog = potato();
    printf("%d\n", frog);

    frog = 1;
    int frogg = 2;
    potato2(&frog, &frogg);
    printf("%d %d\n", frog, frogg);
    return 0;
}

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

int potato(int ** frog)
{
    // int a[1];
    // int * aptr = (int *)malloc(sizeof(int));
    *frog = (int *)malloc(sizeof(int));
    (*frog)[0] = -1; // *(frog + 0) = -1;
    return 0;
}

int main()
{
    int * frog = NULL;
    potato(&frog);
    printf("%d\n", frog[0]);
    return 0;
}

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#include <iostream>

using namespace std;

int potato(int &frog) // int &frog(potato function) = frog(main function)
{
    frog = 11;
    return 0;
}

int main()
{
    int frog = 1;
    potato(frog);
    cout << frog << "\n";
}

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#include <iostream>

using namespace std;


void swap(int &potato, int &frog)
{
    int s = potato;
    potato = frog;
    frog = s;
    return;
}

int main()
{
    int potato, frog;
    cin >> potato >> frog;
    swap(potato, frog);
    cout << potato << frog << "\n";
}

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typedef long long ll;

typedef struct potato{
int frog;
potato* next;
} potato;

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struct potato {
int frog;
potato* next;
};

potato potato1, potato2;
potato1.frog = 1;
potato1.next = &potato2;
potato2.frog = 2;
potato2.next = &potato1;

potato * potato_ptr;
potato_ptr -> frog = potato1.frog;
potato_ptr -> next = potato1.next;

for(int i = 0; i < 10; i++)
{
    cout << potato_ptr -> frog << " ";
    potato_ptr -> frog = (potato1 -> next) -> frog;
    potato_ptr -> next = (potato1 -> next) -> next;
}

potato * potato3, * potato4;
potato3 -> frog = 3;
potato3 -> next = potato4;
potato4 -> frog = 4;
potato4 -> next = potato3;

potato_ptr = potato3;

for(int i = 0; i < 10; i++)
{
    cout << potato_ptr -> frog << " ";
    potato_ptr = potato_ptr -> next;
}

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#include <stdlib.h>
#include "user-defined.h"

#define potato frog

int x = potato; // int x = frog;

#define multiply(potato2, frog2) (potato2 * frog2)

int y, z;

x = multiply(y, z); // x = (y * z);

#undef potato

x = potato; // x = potato

#if 1 == 2
    printf("OMG!\n");
#elif 2 == 3
    printf("LOL\n");
#else
    printf("LGTM!\n");
#endif

#ifndef potato
    #define potato
    #include "potato.h"
#endif