I'm learning C, and trying to print a boolean matrix (5 x 5) from couples of numbers (edges of a graph) in input. If the position of the elements in the matrix has corresponding edges it is "1", otherwise "0". For example:
I put as input: 1 2, 1 4, 2 4, 2 3, 3 5
I want that in the position (1,2) and (2,1); (1,4) and (4,1); (2,4) and (4,2); (2,3) and (3,2), (3,5) and (5,3) it prints 1, but 0 in all the others.
This is what I was able to write, but doesn't really work:
(I have studied multidimensional arrays, but I can't see if they might be useful for this case.)
int i, j;
int array1[5], array2[5];
for (i = 0; i < 5; ++i)
{
printf("Insert the edges %d of the graph\n", i);
scanf("%d %d", &array1[i], &array2[i]);
}
printf("{");
for (i = 0; i < 5; ++i)
printf("(%d,%d)", array1[i], array2[i]);
printf("}\n");
for (i = 0; i < 5; ++i) {
for (j = 0; j < 5; ++j)
if (((array1[i] == i+1) && (array2[i] == j+1)) || ((array1[i] == j+1) && (array2[i] == i+1))) printf("%d ", 1);
else printf("%d ", 0);
printf("\n"); }
What I should see (with those sample inputs):
http://imageshack.com/a/img537/9986/jx5roa.png
What I get:
http://imageshack.com/a/img537/6341/kroVQK.png
Thank you for your time!
You should create the 2-dimensional array. Initially fill it with all zeroes, then when the user enters the edges you change those elements to one.
#define SIZE 5
int array[SIZE][SIZE];
int i, j;
// Initialize array to 0
for (i = 0; i < SIZE; i++) {
for (j = 0; j < SIZE; j++) {
array[i][j] = 0;
}
}
// Get edges from user
for (i = 0; i < SIZE; i++) {
int e1, e2;
printf("Insert the edges %d of the graph\n", i);
scanf("%d %d", &e1, &e2);
// Set them to 1
array[e1-1][e2-1] = 1;
array[e2-1][e1-1] = 1;
}
// Display the array
for (i = 0; i < SIZE; i++) {
for (j = 0; j < SIZE; j++) {
printf("%d ", array[i][j]);
}
printf("\n");
}
Related
I am trying to add numbers from 0 to 9 in the row and 0 to 11 in column of a two dimensional array in C. And as for the rest of the empty spaces, I would like to add 0.
The matrix size is 9 x 11. And this is what the output looks like with the empty blocks filled with 0:
And this is the code I have so far but it does not work:
int i;
int j;
int arr[i][j];
int value = 0;
for (i = 0; i < 9; i++){
for (j = 0; j < 11; j++){
arr[i][j] = value;
printf("%d\n", arr[i][j]);
value++;
}
printf("\n");
}
The screenshot that you've posted has 10 rows and 12 columns, so assuming that, here is the code:
int i;
int j;
int arr[10][12];
for (i = 0; i < 10; i++) {
for (j = 0; j < 12; j++) {
if (i == 0) {
arr[0][j] = j;
} else if (j == 0) {
arr[i][0] = i;
} else {
arr[i][j] = 0;
}
printf("%d", arr[i][j]);
}
printf("\n");
}
Write a program which will accept 2-dimensional square matrix and find out the transpose of it.
Program should not make use of another matrix
Hi I am trying to transpose a 2*2 matrix without using another matrix.
Is there anything wrong with my transpose logic?
I am a newbie
#include <stdio.h>
int main()
{
int mat[2][2];
int i, j, temp;
for (i = 0; i < 2; i++) {
printf("\nEnter elements of %d row of first matrix: ", i + 1); //i+1 so that it can print 1 row, 2 row, 3 row etc
for (j = 0; j < 2; j++) { //loop inside to loop to get value for a[0][0],a[0][1],a[0][2]
scanf("%d", &mat[i][j]);
}
}
printf("The matrix\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[i][j]);
}
printf("\n");
}
//transpose logic using same matrix
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
temp = mat[i][j];
mat[i][j] = mat[j][i];
mat[j][i] = temp;
}
}
printf("The transpose of the matrix is\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[i][j]);
}
printf("\n");
}
}
EDIT: I found an easier way to do it however I still don't understand why my transpose logic by using this
temp = mat[i][j];
mat[i][j] = mat[j][i];
mat[j][i] = temp;
cannot get it to transpose.
Below is my corrected answer
#include <stdio.h>
int main()
{
int mat[2][2];
int i, j, temp;
for (i = 0; i < 2; i++) {
printf("\nEnter elements of %d row of first matrix: ", i + 1);//i+1 so that it can print 1 row, 2 row, 3 row etc
for (j = 0; j < 2; j++) {//loop inside to loop to get value for a[0][0],a[0][1],a[0][2]
scanf("%d", &mat[i][j]);
}
}
printf("The matrix\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[i][j]);
}
printf("\n");
}
printf("The transpose of the matrix is\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[j][i]);
}
printf("\n");
}
}
Your program is a good attempt, but transposing the matrix is like reversing an array: you must stop half way to avoid swapping the transposed values twice, leading to the original matrix as you observe.
You should stop the inner loop when j == i, hence change the inner loop to:
for (j = 0; j < i; j++) { // j < i instead of j < 2
Here is a modified version:
#include <stdio.h>
int main() {
int mat[2][2];
int i, j, temp;
for (i = 0; i < 2; i++) {
printf("\nEnter elements of %d row of first matrix: ", i + 1);
for (j = 0; j < 2; j++) {
if (scanf("%d", &mat[i][j]) != 1)
return 1;
}
}
printf("The matrix:\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[i][j]);
}
printf("\n");
}
//transpose logic using same matrix
for (i = 0; i < 2; i++) {
for (j = 0; j < i; j++) {
temp = mat[i][j];
mat[i][j] = mat[j][i];
mat[j][i] = temp;
}
}
printf("The transpose of the matrix is:\n");
for (i = 0; i < 2; i++) {
for (j = 0; j < 2; j++) {
printf("%d\t", mat[i][j]);
}
printf("\n");
}
return 0;
}
Your corrected answer does not transpose the matrix at all, it merely outputs the transposed matrix. The matrix mat in memory is unchanged.
hi this is my code can you help me out not printing output properly how to print output given in description , i am not getting way to sort the given output, output should be sorted from given average.
Implement fragments using array of pointers.
Rows are static and columns are dynamic. Fixed no.of rows and columns will vary for each row.
Example:
Read no.of rows from user and allocate the memory statically for rows.
Read no.of columns for each row and allocate the memory dynamically.
Let us Assume, Row = 3.
Row[0] = 4 columns, Row[1] = 3 columns and Row[2] = 5 columns.
While allocating the memory for columns you have allocate for no.of columns + 1 dynamically.
After that read the values from user and calculate the average for each row separately and store that average in that extra memory block which you added while allocating the memory.
Then sort the array based on the average.
Print the output on the screen.
Example is given below.
ENTER THE NUMBER OF ARRAY YOU WANT TO GIVE AS INPUT: 3
ENTER NO. OF COLUMNS IN ROW[0]: 3
ENTER NO. OF COLUMNS IN ROW[1]: 3
ENTER NO. OF COLUMNS IN ROW[2]: 3
ENTER 3 VALUES OF ROW[0]: 2 3 5
ENTER 3 VALUES OF ROW[1]: 2 4 7
ENTER 3 VALUES OF ROW[2]: 2 1 0
BEFORE SORTING OUTPUT IS:
2 3 5 3.33333
2 4 7 4.33333
2 1 0 1
AFTER SORTING OUTPUT IS:
2 1 0 1
2 3 5 3.33333
2 4 7 4.33333
My code so far:
#include <stdio.h>
#include <stdlib.h>
int fragments(int rows, int *array)
{
int i, j;
int pos[rows];
float *arr[rows], avg, sum;
char *temp[rows];
for (i = 0; i < rows; i++)
{
arr[i] = malloc(sizeof(float*) * array[i]+1);
pos[i] = i;
printf("Enter %d values for row[%d]: ", array[i], i);
for (j = 0; j< array[i]; j++)
{
scanf(" %f", &arr[i][j]);
}
}
printf("Before Sorting output is:\n");
for (i = 0; i < rows; i++)
{
sum = 0;
for (j = 0; j < array[i]; j++)
{
printf("%f ", arr[i][j]);
sum = sum + arr[i][j];
}
printf("%f\n", arr[i][j] = (sum / j));
}
for (i = 0; i < rows - 1; i++)
{
for (j = 0; j < rows - i - 1; j++)
{
if (arr[j][array[j]] > arr[j+1][array[j+1]])
{
temp[j][j] = arr[j][array[j]];
arr[j][array[j]] = arr[j+1][array[j+1]];
arr[j+1][array[j+1]] = temp[j][j];
}
}
}
for (i = 0; i < rows; i++)
{
for (j = 0; j < array[i] + 1; j++)
{
printf("%f ", arr[i][array[j]]);
}
printf("\n");
}
}
int main()
{
int rows, i, j;
printf("Enter no of rows: ");
scanf("%d", &rows);
int array[rows];
int pos[rows];
for (i = 0; i < rows; i++)
{
printf("Enter no of columns in row[%d]:", i);
scanf("%d", &array[i] );
}
fragments(rows, array); //`enter code here`
}
There are multiple problems in your code:
The allocation size is incorrect: arr[i] = malloc(sizeof(float*) * array[i]+1); should read:
arr[i] = malloc(sizeof(float) * (array[i] + 1));
the swapping code should swap the array pointers and the array sizes. The current code does not make sense. Use this instead:
float *temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
int temp1 = array[j];
array[j] = array[j+1];
array[j+1] = temp1;
the final print loop is incorrect: instead of printf("%f ", arr[i][array[j]]); you should write:
printf("%f ", arr[i][j]);
Here is a modified version:
#include <stdio.h>
#include <stdlib.h>
int fragments(int rows, int *array) {
float *arr[rows];
for (int i = 0; i < rows; i++) {
arr[i] = malloc(sizeof(float) * (array[i] + 1));
printf("Enter %d values for row[%d]: ", array[i], i);
for (int j = 0; j < array[i]; j++) {
if (scanf("%f", &arr[i][j]) != 1)
return;
}
}
printf("Before Sorting output is:\n");
for (int i = 0; i < rows; i++) {
float sum = 0;
for (j = 0; j < array[i]; j++) {
printf("%f ", arr[i][j]);
sum += arr[i][j];
}
printf("%f\n", arr[i][j] = sum / j);
}
for (int i = 0; i < rows - 1; i++) {
for (int j = 0; j < rows - i - 1; j++) {
if (arr[j][array[j]] > arr[j+1][array[j+1]]) {
float *temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
int temp1 = array[j];
array[j] = array[j+1];
array[j+1] = temp1;
}
}
}
for (int i = 0; i < rows; i++) {
for (int j = 0; j < array[i] + 1; j++) {
printf("%f ", arr[i][j]);
}
printf("\n");
}
for (int i = 0; i < rows; i++) {
free(arr[i]);
}
}
int main() {
int rows;
printf("Enter no of rows: ");
if (scanf("%d", &rows) != 1)
return 1;
int array[rows];
for (int i = 0; i < rows; i++) {
printf("Enter no of columns in row[%d]:", i);
if (scanf("%d", &array[i]) != 1)
return 1;
}
fragments(rows, array);
return 0;
}
I'm asked to find the highest frequency from an array of elements and all elements with said frequency. My code seem to work just fine but it seems to have a mistake somewhere when i submit it. Can anyone help me find the error?
Format Input:
The first line contains an integer T stating the number of test cases. For each test case, the first line contains a single integer N which indicate the number of element in the array. The next line contains N integers Xi (1≤i≤N) which indicate ith element in the array.
Format Output:
Consists of T lines where each line has the format “Case #X: Y ”, where X is the test case number starting at 1 and Y is the highest frequency. Next line contains all elements which have that frequency sorted in ascending order.
Constraints:
1 ≤ T ≤ 20 | 2 ≤ N ≤ 20.000 | 1 ≤ Xi ≤ 2 × 10^5
Sample Input:
3
8
1 1 2 2 3 4 5 5
8
5 5 4 3 2 2 1 1
4
1 1 1 3
Sample Output:
Case #1: 2
1 2 5
Case #2: 2
1 2 5
Case #3: 3
1
Here is my code:
#include <stdio.h>
int main() {
int T, N[20];
scanf("%d", &T); getchar();
int A[T][20000];
for (int i = 0; i<T; i++) {
scanf("%d", &N[i]); getchar();
for (int j = 0; j<N[i]; j++) {
scanf("%d", &A[i][j]); getchar();
}
int X = 0;
for (int j = 0; j<N[i]; j++) {
for (int k = j + 1; k<N[i]; k++) {
if (A[i][k]<A[i][j]) {
X = A[i][j];
A[i][j] = A[i][k];
A[i][k] = X;
}
}
}
}
int f[20000];
for (int i = 0; i<T; i++) {
int c = 0, mc = 0;
for (int j = 0; j<N[i]; j++) {
c = 1;
if(A[i][j] != -1) {
for (int k = j+1; k<N[i]; k++) {
if (A[i][j] == A[i][k]) {
c++;
A[i][k] = -1;
}
}
f[j]=c;
}
if (c>mc) {
mc = c;
}
}
printf("Case #%d: %d\n", i+1, mc);
for (int j = 0; j<N[i]; j++) {
if (A[i][j] != -1) {
if (f[j] == mc) {
printf ("%d", A[i][j]);
if (j<N[i]-1) {
printf(" ");
}
}
}
}
printf("\n");
}
return 0;
}
EDIT
So I made another code where instead of inputting all arrays at once and outputting everything at once, this code outputs the frequency and elements after i input the first arrays of numbers. But it seems like the code still have problems and i can't find where... P.s I'm pretty new to this, so i apologise for the lack of efficiency of my codes.
NEW CODE
#include <stdio.h>
int main() {
int T, N;
scanf("%d", &T); getchar();
int A[20000];
for (int i = 0; i<T; i++) {
scanf("%d", &N); getchar();
for (int j = 0; j<N; j++) {
scanf("%d", &A[j]); getchar();
}
int X;
for (int j = 0; j<N; j++) {
for (int k = j + 1; k<N; k++) {
if (A[k]<A[j]) {
X = A[j];
A[j] = A[k];
A[k] = X;
}
}
}
int f[N], c = 0, mc = 0;
for (int j = 0; j<N; j++) {
c = 1;
if(A[j] != -1) {
for (int k = j+1; k<N; k++) {
if (A[j] == A[k]) {
c++;
A[k] = -1;
}
}
f[j]=c;
if (c>mc) {
mc = c;
}
}
}
printf("Case #%d: %d\n", i+1, mc);
for (int j = 0; j<N; j++) {
if (A[j] != -1) {
if (f[j] == mc) {
printf ("%d", A[j]);
if (j<N-1) {
printf(" ");
}
}
}
}
printf("\n");
}
return 0;
}
It took me a couple of days but i finally got how to do this. Apparently, it was not as complicated as i thought... here is the working code. Thanks to everyone who helped :)
#include <stdio.h>
int main() {
int T, N;
scanf("%d", &T);
for (int i = 0; i<T; i++) {
scanf("%d", &N); getchar();
//INPUT elements and counting frequncy for each element
int f[200001] = {0}, E = 0;
for (int j = 0; j<N; j++) {
scanf("%d", &E); getchar();
f[E]++;
}
//find max frequency and how many elements with max frequency
int max = 0, c = 0;
for (int j = 1; j<200001; j++) {
if (f[j] == max) {
c ++;
}
if (f[j]>max) {
max = f[j];
c = 1;
}
}
//OUTPUT result
printf("Case #%d: %d\n", i+1, max);
int counter = 0;
for (int j = 1; j<200001; j++) {
if (f[j] == max) {
counter ++;
if (counter<c){
printf("%d ", j);
} else {
printf("%d\n", j);
}
}
}
}
return 0;
}
Good day to everybody. My task is to determine if a rectangular matrix has two rows of positive elements. I write the code below. At end I try to chect statement about positive row, but it's not working at all. Please explain me how to correct get the access to the each row and column in matrix, and meaybe edit my code.
#include <stdio.h>
#include <conio.h>
#include <locale.h>
#define M 3
#define N 4
int main(){
setlocale(LC_ALL, "Rus");
float a[M][N]; //set matrix with 3 row and 4 column
int i, j; // row and column index
int count;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
scanf_s("%f", &a[i][j]);
}
for (i = 0; i < M; i++){
printf("%d-я строка:", i + 1);
for (j = 0; j < N; j++)
printf("%f", a[i][j]);
printf("\n");
}
count = 0;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
if (a[i][j] > 0){
count++;
printf("%d", count);
}
}
_getch();
return 0;
}
When counting the number of positive elements in a row, you need to set the count back to zero for each row.
So instead of:
count = 0;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
if (a[i][j] > 0){
count++;
printf("%d", count);
}
}
you need
for (i = 0; i < M; i++){
count = 0;
for (j = 0; j < N; j++) {
if (a[i][j] > 0){
count++;
}
}
printf("row %d has %d positive elements\n", i, count);
}