I would like to return a shape(trapezium) with bases 6 and 3 given integers 3 and 4 and a char.
I have tried implementing this with code below but I am getting a rectangle instead
#include <stdio.h>
char my_array[];
char *ptr;
int m = 3,n =4;
int main(void)
{
int i,j;
ptr = &my_array[0];
for (j = 0;j < n ;++j)
{
for (i = 0; i < m+n-1; i++)
{
my_array[i] = '*';
printf("%c ",my_array[i]);
}
printf("\n");
}
return 0;
}
I would like to know how I can reduce the length of each row of the result above to get the shape i need.Any ideas?
You probably meant to use i < m + j - 1 in your second for loop:
#include <stdio.h>
const int m = 3, n = 4;
int main(void){
int i, j;
const char symb = '*';
for (j = 0; j < n ;++j){
for (i = 0; i < m + j - 1; i++)
printf("%c ",symb);
printf("\n");
}
return 0;
}
Related
I want to create an array of 100 size, which its elements are unique random integers from 1 to 999999. My code doesn't give any error message or the output that I want. What is wrong with this?
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 100
#define EMPTY -1
int main() {
srand(time(NULL));
int list[999999], A[N], i;
for (i = 0; i < N; i++)
A[i] = EMPTY;
for (i = 0; i < 999999; i++) {
list[i] = i + 1;
}
for (i = 0; i < 999999; i++) {
int j = rand() % 999999;
int temp = list[i];
list[i] = list[j];
list[j] = temp;
}
for (i = 0; i < N; i++) {
A[i] = list[i];
}
for (i = 0; i < N; i++) {
printf("%i\n", A[i]);
}
}
The initial loop is useless, the method is very inefficient, but the output should meet the goal...
Yet there might be an issue with the list array: it is very large and defining it as a local variable with automatic storage cause a stack overflow, depending on your target system. Try defining is as:
static int list[999999];
Here is an alternative for N small compared to 1000000:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 100
int main() {
int A[N], i, j;
srand(time(NULL));
for (i = 0; i < N;) {
int n = 1 + rand() % 999999;
for (j = 0; j < i; j++) {
if (A[j] == n)
break;
}
if (i == j)
A[i++] = n;
}
for (i = 0; i < N; i++) {
printf("%i\n", A[i]);
}
return 0;
}
I spent hours in printing a lower triangle in C. However, I just cannot figure out how to solve this same question with array.
Below is one of the solution I found on net:
int main(void)
{
char ch='A';
int i,j;
for(i=1;i<7;i++)
{
for(j=0;j<i;j++)
printf("%c",ch++);
printf("\n");
}
return 0;
}
Below is how I try to do the same thing:
#define SIZE 8
int main(void){
char Alphabet[SIZE];
int i, j;
for (i = 0, j = 'A'; i < SIZE, j < 'A' + SIZE; i++, j++){
Alphabet[i] = j;
}
for (i = 0; i <= 7; i++){
for (j = 0; j <= i; j++){
printf("%c", Alphabet[j+i]);
}
printf("\n");
}
return 0;
}
The result of the code above is :
A
BC
CDE
DEFG
EFGHI
FGHIJK
GHIJKLM
HIJKLMNO
What should I revise if I want to print as follow:
A
BC
DEF
GHIJ
KLMNO
PQRSTU
Thank you.
Keep a track of elements printed from the Alphabet array so far and in the inner loop start printing from next element onward. You can do:
#include <stdio.h>
#define SIZE 26
int main(void) {
char Alphabet[SIZE];
for (int i = 0; i < SIZE; i++) {
Alphabet[i] = 'A' + i;
}
// Or simply have the Alphabet array initialized like this
// char Alphabet[SIZE] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int k = 0;
for (int i = 0; i < 6; i++) {
for (int j = 0; j <= i && k < SIZE; j++) {
printf("%c", Alphabet[k++]);
}
printf("\n");
}
return 0;
}
Output:
# ./a.out
A
BC
DEF
GHIJ
KLMNO
PQRSTU
EDIT:
In the comments, a fellow SO contributor said that the above approach is same as the one OP already found as a solution and OP might be looking for approach of calculating the Alphabet array index using i and j only and without use of variable keeping track of array index. Below is the program which does not use any extra variable to keep the track of Alphabet array index to print characters in inner loop and calculating the index using i and j:
#include <stdio.h>
#define SIZE 26
#define ARRLOC(x) ((x * ((x + 1) / 2)) + ((x % 2 == 0) ? (x / 2) : 0))
int main(void) {
char Alphabet[SIZE];
for (int i = 0; i < SIZE; i++){
Alphabet[i] = 'A' + i;
}
// Or simply have the Alphabet array declared like this
// char Alphabet[SIZE] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for (int i = 0; i < 6; i++){
for (int j = 0; j <= i && (ARRLOC(i) + j) < SIZE; j++){
printf("%c", Alphabet[ARRLOC(i) + j]);
}
printf("\n");
}
return 0;
}
Output:
# ./a.out
A
BC
DEF
GHIJ
KLMNO
PQRSTU
You can just have a third 'index' variable that keeps track of which letter to output across both loops (I've called this k in the code below). Also, you need to make your Alphabet array bigger (26 seems like a reasonable number); then, if that k variable gets past 'Z', we can simply loop back to 'A' using the modulo operator (%):
#include <stdio.h>
#define SIZE 26
int main(void)
{
char Alphabet[SIZE];
int i, j, k;
for (i = 0; i < SIZE; i++) Alphabet[i] = 'A' + i;
int k = 0;
for (i = 0; i <= 7; i++) {
for (j = 0; j <= i; j++) {
printf("%c", Alphabet[k % 26]); // If past the end, loop back with the "%" operator
++k;
}
printf("\n");
}
return 0;
}
Or we can make the code a little more 'succinct' (though perhaps less clear) by initializing the k variable at the start of the outer loop and incrementing at the end of the inner loop:
for (k = i = 0; i <= 7; i++) { // Initialize "k" here ...
for (j = 0; j <= i; j++, k++) { // .. but increment it here!
printf("%c", Alphabet[k % 26]); // If past the end, loop back with the "%" operator
}
printf("\n");
}
If you want an 8 by 8 pyramid, you won't have enough characters to do it using the alphabet (requires 36), so I made the alphabet repeat itself (u could also make it go to numeric instead?)
#define SIZE 8
int area(int size);
int main(void){
char Alphabet[area(SIZE)];
int i, j;
for (i = 0, j = 'A'; i < area(SIZE); i++, j++){
if (j > 'Z') j = 'A';
Alphabet[i] = j;
}
int idx=0;
for (i = 0; i < SIZE; i++){
for (j = 0; j <= i; j++){
printf("%c", Alphabet[idx++]);
}
printf("\n");
}
return 0;
}
int area(int size) {
if (size==1) return 1;
return size + area(size - 1);
}
Given two arrays: int nums[N] and int *ptrs[N] (N is a constant number).
I have to initialize the first array with some numbers. After that, i have to initialize the second array, so every element of the second array points to the element with the same index of the first array. (ptrs[0] points to nums[0],...).
Now i have to write a function with "ptrs" as argument that modifies the pointers in such a way that the first element of the second array points to the smallest number in the first array,..)
It's not allowed to change the "nums-array", i can only change the "ptrs-array".
This is my code i already have, but when i run it, the "nums-array" changes too.
What do i do wrong?
#include <stdio.h>
#define N 6
void sort(int *ptrs);
int main()
{
int nums[N] = { 1,6,7,8,2,5 };
int(*ptrs)[N];
int i;
ptrs = nums;
sort(ptrs);
for (i = 0; i < N; i++)
printf("nummer is: %d en %d\n", (*ptrs)[i], nums[i]);
return 0;
}
void sort(int *ptrs)
{
int i, j, tmp;
for (i = 0; i < N; i++)
for (j = i + 1; j < N; j++)
if ((ptrs)[i] > (ptrs)[j])
{
tmp = (ptrs)[i];
(ptrs)[i] = (ptrs)[j];
(ptrs)[j] = tmp;
}
}
Fix for the first part:
int main()
{
int nums[N] = { 1,6,7,8,2,5 };
int *ptrs[N]; // fix
int i;
for(i = 0; i < N; i++) // fix
ptr[i] = nums+i; // fix (or ptr[i] = &nums[i])
I found the solution, thanks for helping guys!
#include <stdio.h>
#define N 6
void sort(int ptrs[], int nums[]);
int main()
{
int nums[N] = { 1,6,7,8,2,5 };
int i,j,*p, *ptrs[N];
for (i = 0; i < N; i++) {
ptrs[i] = &nums[i];
}
sort(ptrs, nums);
return 0;
}
void sort(int *ptrs[], int nums[])
{
int i, j, tmp, p[N];
for (i = 0; i < N; i++)
p[i] = *ptrs[i];
for(j = 0; j < N; j++)
for (i = 0; i <= N; i++)
if (p[i] > p[i+1])
{
tmp = (ptrs)[i];
(ptrs)[i] = (ptrs)[i+1];
(ptrs)[i+1] = tmp;
for (i = 0; i < N; i++)
p[i] = *ptrs[i];
}
for (i = 0; i < N; i++)
printf("nummer is: %d en %d\n", *ptrs[i], nums[i]);
return;
}
I have got some more problems with the code. This program ask the user to specify the nr of throws then it throws 3 dices and add these 3 dices to sum.
Then another function sorts the sum form the smallest to the largest with a bubble sorting algorithm.
the first two functions seems to work but the program does not print out the result of the 3rd sorting function.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX 100
//This function ask the user for the amout of throws
int numberofthrows() {
int throws
printf("Type in the number of throws");
scanf("%d", &throws);
return throws;
}
//This function makes the random throws of 3 dices with regard to the number of throws
int filler(int thrownr, int dice1[MAX], int dice2[MAX], int dice3[MAX], int sum[MAX]) {
int i, nr;
srand(time(NULL));
for(i = 0; i <= thrownr; i++) {
nr = rand()%6;
dice1[i] = nr + 1;
nr = rand()%6;
dice2[i] = nr + 1;
nr = rand()%6;
dice3[i] = nr + 1;
sum[i] = dice1[i] + dice2[i] + dice3[i];
}
int j;
for(j = 0; j <= thrownr; j++) {
printf("%d ", dice1[j]);
printf("%d ", dice2[j]);
printf("%d ", dice3[j]);
printf("%d\n", sum[j]);
}
}
//This function sorts the result in form the sum array
int sorter(int thrownr, int sum[MAX], int sortsum[MAX]) {
int tmp, i, j, k, m;
for(i = 0; i <= thrownr; i++) {
sortsum[i] = sum[i];
}
for(m = 0; m <= 10; m++) {
for(j = 0; j <= thrownr; i++) {
if (sortsum[j] > sortsum[j+1]) {
tmp = sortsum[j];
sortsum[j] = sortsum[j+1];
sortsum[j+1] = tmp;
}
}
}
for(k = 0; k <= thrownr; k++) {
printf("%d\n", sortsum[k]);
printf("%d\n", sum[k]);
}
}
int main(void) {
srand(time(NULL));
int dice1[MAX];
int dice2[MAX];
int dice3[MAX];
int sum[MAX];
int sortsum[MAX];
int numberofthrows2;
numberofthrows2 = numberofthrows();
filler(numberofthrows2, dice1, dice2, dice3, sum);
sorter(numberofthrows2, sum, sortsum);
return 0;
}
The code for sorting is a bit wrong. Change
for(m = 0; m <= 10; m++)
To
for(m = 0; m <= thrownr-1; m++)
And
for(j = 0; j <= thrownr; i++)
To
for(j = 0; j < thrownr-m-1; i++)
To fix it. Also, call srand once at the start of main. Don't call it more than once in a program or you might get the same "random" numbers everytime you run your program.
I'm working on my class project and I'm currently stuck at the most basic one. Basically I have to fill the stack of boxes using loops and 3d array. The stack is 4 width, 4 length and 3 height and I have to fill boxes with 100 items each.
void main(){
int boxShleve[3][4][4];
int i, j, k;
for (i=0; i<3; ++i){
for (j=0; j<4; ++j){
for (k=0; k<4; ++k){
boxShleve[3][4][4] = 100;
}
}
}
printf("%d", boxShleve[3][4][4]);
}
This is the broken piece of my work... How do I make each array has 100 element in it?
This is what you meant to do:
int main()
{
int boxShleve[3][4][4];
int i, j, k;
for (i = 0; i < 3; ++i)
for (j = 0; j < 4; ++j)
for (k = 0; k < 4; ++k)
boxShleve[i][j][k] = 100;
for (i = 0; i < 3; i++)
for (j = 0; j < 4; j++)
for (k = 0; k < 4; k++)
printf("%d ", boxShleve[i][j][k]);
return 0;
}
The reason you need the nested loops is to use the i, j and k as indexes to access the array. So you have to use them.
Same for printing the values.
A faster way to do this if you are using GCC is as follows.
int boxShleve[3][4][4] = {
{[0 ... 2] = 100 },
{[0 ... 3] = 100 },
{[0 ... 3] = 100 } };
#include <stdio.h>
int main(){
int boxShleve[3][4][4];
size_t size = sizeof(boxShleve)/sizeof(int);
int *p = &boxShleve[0][0][0];
while(size--)
*p++ = 100;
printf("%d\n", boxShleve[2][3][3]);//last element,
return 0;
}