Answer to Question #223675 in C for Neil

Question

1. Write a C program to arrange row elements in ascending order using functions & dynamic memory allocation.

 

2. Write a C program to arrange column elements in ascending order using functions &

dynamic memory allocation.

Answer 1

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

typedef struct matrix {
    int n, m;
    int *val;
} Matrix;

Matrix* alloc_mat(int n, int m);
void free_mat(Matrix* mat);
int get_el(Matrix* mat, int i, int j);
void set_el(Matrix* mat, int i, int j, int x);
void rand_mat(Matrix* mat, int imin, int imax);
void print_mat(Matrix* mat);
void sort_row(Matrix* mat);
void sort_col(Matrix* mat);

int main()
{
    Matrix* m;
    srand(time(NULL));
    
    m = alloc_mat(3, 4);
    rand_mat(m, 1, 10);
    printf("Original matrix:\n");
    print_mat(m);
    printf("\nSorted by row:\n");
    sort_row(m);
    print_mat(m);
    printf("\nSorted by column:\n");
    sort_col(m);
    print_mat(m);
    free_mat(m);
    
    return 0;
}

int get_el(Matrix* m, int i, int j) {
    if (i<0 || i>= m->n) {
        printf("Error row index %d out of range (%d)\n", i, m->n);
        exit(1);
    }
    if (j<0 || j>=m->m) {
        printf("Error col index %d out of range (%d)\n", j, m->m);
        exit(1);
    }
    return m->val[i*m->m + j];
}

void set_el(Matrix* m, int i, int j, int x) {
    if (i<0 || i>= m->n) {
        printf("Error row index %d out of range (%d)\n", i, m->n);
        exit(1);
    }
    if (j<0 || j>=m->m) {
        printf("Error col index %d out of range (%d)\n", j, m->m);
        exit(1);
    }
    m->val[i*m->m + j] = x;
}

Matrix* alloc_mat(int n, int m) {
    Matrix* mat = (Matrix*) malloc(sizeof(struct matrix));
    mat->n = n;
    mat->m = m;
    mat->val = (int *) malloc(sizeof(int)*m*n);
    return mat;
}

void free_mat(Matrix* mat) {
    free(mat->val);
    free(mat);
}

void rand_mat(Matrix* mat, int imin, int imax) {
    int i, j, x;
    for (i=0; i<mat->n; i++) {
        for (j=0; j<mat->m; j++) {
            x = rand() % (imax - imin) + imin;
            set_el(mat, i, j, x);
        }
    }
}

void print_mat(Matrix* mat) {
    int i, j;
    
    for (i=0; i<mat->n; i++) {
        printf("[");
        for (j=0; j<mat->m-1; j++) {
            printf("%d, ", get_el(mat, i, j));
        }
        printf("%d ]\n", get_el(mat, i, mat->m-1));
    }
}

void sort_row(Matrix* mat) {
    int i, j, k, k_min, x;
    
    for (i=0; i<mat->n; i++) {
        for (j=0; j<mat->m-1; j++) {
            k_min = j;
            for (k=j+1; k<mat->m; k++) {
                if (get_el(mat, i, k) < get_el(mat, i, k_min)) {
                    k_min = k;
                }
            }
            if (k_min != j) {
                x = get_el(mat, i, j);
                set_el(mat, i, j, get_el(mat, i, k_min));
                set_el(mat, i, k_min, x);
            }
        }
    }
}

void sort_col(Matrix* mat) {
    int i, j, k, k_min, x;
        
    for (j=0; j<mat->m; j++) {
        for (i=0; i<mat->n-1; i++) {
            k_min = i;
            for (k=i+1; k<mat->n; k++) {
                if (get_el(mat, k, j) < get_el(mat, k_min, j)) {
                    k_min = k;
                }
            }
            if (k_min != i) {
                x = get_el(mat, i, j);
                set_el(mat, i, j, get_el(mat, k_min, j));
                set_el(mat, k_min, j, x);
            }
        }
    }
}