start king

qscr/c/learnc/aptr.c

@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+    int i, j;
+    /* TODO: define the 2D pointer variable here */
+    int ** pnumbers;
+
+    /* TODO: complete the following line to allocate memory for holding three rows */
+    pnumbers = (int **) malloc(sizeof(int)*6);
+
+    /* TODO: allocate memory for storing the individual elements in a row */
+    pnumbers[0] = (int *) malloc(1 * sizeof(int));
+    pnumbers[1] = (int *) malloc(2 * sizeof(int));
+    pnumbers[2] = (int *) malloc(3 * sizeof(int));
+
+    pnumbers[0][0] = 1;
+    pnumbers[1][0] = 1;
+    pnumbers[1][1] = 1;
+    pnumbers[2][0] = 1;
+    pnumbers[2][1] = 2;
+    pnumbers[2][2] = 1;
+
+    for (i = 0; i < 3; i++) {
+        for (j = 0; j <= i; j++) {
+            printf("%d", pnumbers[i][j]);
+        }
+        printf("\n");
+    }
+
+    for (i = 0; i < 3; i++) {
+        /* TODO: free memory allocated for each row */
+        free(pnumbers[i]);
+    }
+
+    /* TODO: free the top-level pointer */
+    free(pnumbers);
+  return 0;
+}

qscr/c/learnc/bsort.c

@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+struct Darray {
+    int size;
+    int data[]; //flexible array member
+};
+
+//randomized array
+void rarr(struct Darray *darr) {
+    for (int i=0; i<darr->size; ++i) {
+        darr->data[i] = rand() % 32;
+    }
+    if (darr == NULL) {
+        printf("failed");
+        exit(1);
+    }
+}
+
+struct Darray *createdarray(int mysize){
+    struct Darray *darrstruct = malloc(mysize * sizeof(int) + sizeof(*darrstruct));
+
+    if (darrstruct == NULL) {
+        printf("failed");
+        exit(1);
+    }
+
+    darrstruct->size = mysize;
+    rarr(darrstruct);
+
+    return darrstruct;
+}
+
+void msort(int *myarr, int mysize) {
+    for (int i = 0 ; i < mysize; i++) {
+        for (int j = 0 ; j < mysize ; j ++)
+            if (myarr[i] > myarr[j]) {
+                int k = myarr[i];
+                myarr[i] = myarr[j];
+                myarr[j] = k;
+            }
+    }
+}
+
+void bsort(struct Darray *myarr) {
+    for (int i = 0; i < myarr->size; i++) {
+        for (int j = 0; j < myarr->size -1 ; j++ ) {
+            if (myarr->data[j] < myarr->data[j+1]) {
+                int k = myarr->data[j];
+                myarr->data[j] = myarr->data[j+1];
+                myarr->data[j+1] = k;
+            }
+        }
+    }
+ }
+
+int main() {
+    srand(time(NULL));
+    int mysize = 7;
+    struct Darray *myarray;
+    myarray = createdarray(mysize);
+
+    printf("myarr:\n");
+    for (int i = 0 ; i < myarray->size; i++) {
+        printf("%d\n", myarray->data[i]);
+    }
+
+    bsort(myarray);
+
+    printf("sorted myarr:\n");
+    for (int i = 0 ; i < myarray->size; i++) {
+        printf("%d\n", myarray->data[i]);
+    }
+
+    free(myarray);
+
+    return 0;
+
+}

qscr/c/learnc/linkedlist.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct node {
+    int val;
+    struct node * next;
+};
+
+struct node_t * head = NULL;
+head = (struct node_T*)malloc(sizeof(struct node_t));
+
+int main(){
+
+    return 0;
+}

qscr/c/learnc/pascaltriangle.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int *pascallarr(int iarrsize, int *ptr){
+    int *mypascallar = malloc(sizeof(int) * iarrsize + 1);
+    /* declare edges, as they're always 1 anyways so we can start the loop at 1 (so i-1 = 0) */
+    mypascallar[0] = 1;
+    mypascallar[iarrsize] = 1;
+    for (int i = 1; i <= iarrsize; i++) {
+        if (i < iarrsize) {
+            mypascallar[i] = ptr[i-1] + ptr[i];
+        }
+    }
+    return mypascallar;
+}
+
+int main() {
+    int trianglesize = 18;
+    int ** pnumbers;
+
+    /* create pascals triangle, on row i, we have i numbers */
+
+    /* should create 2d array of ints, with an array of pointers to arrays*/
+
+    int **ptrtriangle = malloc(sizeof(int *)*trianglesize);
+
+    /* need to create a function that returns the pointer to an array of i numbers filled with numbers */
+    for (int i = 0; i < trianglesize; i++) {
+        ptrtriangle[i] = pascallarr(i,ptrtriangle[i-1]);
+        for (int j = 0; j <= i; j++) {
+            printf("%d|",ptrtriangle[i][j]);
+        }
+        printf("\n");
+    }
+    return 0;
+}

qscr/c/learnc/rec.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int recfact(int x){
+    int y = 1;
+    if (x==1){
+        return y;
+    } else {
+        return y *= x *recfact(x-1);
+    }
+}
+
+int recfor(int x){
+    int gaga = 1;
+    for (int i = 1; i < x;) {
+        gaga *= i++;
+    }
+    return gaga;
+}
+
+/*
+ * i = 1, gaga = 1*2
+ * i = 2, gaga = 1*2*3 = 6
+ * i = 3, 1*2*3*4 = 24
+ *
+ * wrong loop time condition
+ * wrong calculation
+ *
+ * ---
+ *
+ * recursion
+ *
+ * forgot to assign, forgot a number (multiplied by 0)
+ * misunderstood calculation
+
+ wel exploren, maar wel naar een doel.
+ kijken naar auxililiaries.
+ curiosity wss, leren vragen. leren wat ik niet heb, weten wat ik niet weet.
+
+ zoektocht heeft wat sturing nodig.
+
+ hoe ik mijn probeer stel/vind
+ het probleem onderzoeken
+
+ limiteer de pogingen
+
+
+ hardware / networking
+ * *  */
+
+int main () {
+    int i = 6; // we can not handle negative numbers
+
+    printf("%d\n", recfor(i));
+    printf("%d\n", recfact(i));
+
+    return 0;
+}

qscr/c/learnc/rec2.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+ * factorials
+ *
+ * in both for loop, as well as recursive
+ * factorial: voor int i, vermenigvuldig dan elke i to je bij 1 komt (uit gaande van positive ints)
+ *
+ * dus, f(3)=3*2*1 = 6 ; f(4)=4*3*2*1=24 ; f(a)=no ; f(-2)= no ; f(2.1) = no
+ *
+ * will use 2 functions:
+ * recfac using recursion
+ * itfac using iteration
+ *
+ * should probably figure out how to test this? maybe a dumb K:V?
+ * *  */
+
+int recfact(int input){
+    int fac = 1;
+    if (input==1) {
+        return fac;
+    }
+    else {
+        fac *= input * recfact(input-1);
+    }
+}
+
+int itfact(int input){
+    int sum = 1;
+    for (int i = 1; i <= input; i++) {
+        sum *= i;
+    }
+    return sum;
+}
+
+int main(){
+
+    int input = 5;
+
+    //recfact(input);
+    //itfact(input);
+    printf("%d\n", recfact(input));
+    printf("%d\n", itfact(input));
+    return 0;
+}