Question

I am having problems getting the insertion sort function to output in descending order. Also, the initialize array function is not being called when I test it in the main function. I am wondering why it prints out the original array instead of initializing. Thank you.

#include <stdio.h>

void print_array(int *array, int length){
int i;
for(i=0; i<length;i++)
printf("%d"",",array[i]);
printf("\n");
}

void initialize_array(int *array, int length){
int i;
for(i=0, i<length; i++;){
if (i%2 ==0)
array[i]= 5;
else
array[i]= 0;
}
}

void insertion_sort(int array [], int length){
int i,j,a;
for(j =1; j<length;j++){
a = array[j];
for(i= j-1; i>=0 && array[i] > a;i--)
array[i+1]= array[i];
array[i+1]= a;
}
  
}

int factorial(int num){
if(num==0)
return 1;
else
return num* factorial(num-1);
}

int main()
{
int a[] = {2, 5, 7, 9, 12, 13, 15, 17, 19, 20};
int b[] = {18, 16, 19, -5, 3, 14, 6, 0};
int c[] = {4, 2, 5, 3, 1};

/* testing initialize_array */
print_array(a, sizeof(a)/sizeof(a[0])); /* print: 2, 5, 7, 9, 12, 13, 15, 17, 19, 20 */
initialize_array(a, sizeof(a)/sizeof(a[0]));
print_array(a, sizeof(a)/sizeof(a[0])); /* print: 5, 0, 5, 0, 5, 0, 5, 0, 5, 0 */

/* testing insertionSort */
print_array(b, sizeof(b)/sizeof(b[0])); /* print: 18, 16, 19, -5, 3, 14, 6, 0 */
insertion_sort (b, sizeof(b)/sizeof(b[0]));
print_array(b, sizeof(b)/sizeof(b[0])); /* print: 19, 18, 16, 14, 6, 3, 0, -5 */

/* testing factorial */
printf("%d\n", factorial(5)); /* print: 120 */

c[0] = factorial (c[0]);
c[1] = factorial (c[2]);
print_array(c, sizeof(c)/sizeof(c[0])); /* print: 24, 120, 5, 3, 1 */

return 0;
}

Answer 1

#include <stdio.h>

void print_array(int *array, int length) {
    int i;
    for (i = 0; i < length; i++)
        printf("%d"",", array[i]);
    printf("\n");
}

void initialize_array(int *array, int length) {
    int i;
    for (i = 0; i < length; i++) {
        if (i % 2 == 0)
            array[i] = 5;
        else
            array[i] = 0;
    }
}

void insertion_sort(int array[], int length) {
    int temp;
    for (int i = 1; i < length; i++) {
        for(int j = i; j > 0; j--) {
            if(array[j] > array[j-1]) {
                temp = array[j];
                array[j] = array[j-1];
                array[j-1] = temp;
            }
        }
    }
}

int factorial(int num) {
    if (num == 0)
        return 1;
    else
        return num * factorial(num - 1);
}


int main() {
    int a[] = {2, 5, 7, 9, 12, 13, 15, 17, 19, 20};
    int b[] = {18, 16, 19, -5, 3, 14, 6, 0};
    int c[] = {4, 2, 5, 3, 1};

/* testing initialize_array */
    print_array(a, sizeof(a) / sizeof(a[0])); /* print: 2, 5, 7, 9, 12, 13, 15, 17, 19, 20 */
    initialize_array(a, sizeof(a) / sizeof(a[0]));
    print_array(a, sizeof(a) / sizeof(a[0])); /* print: 5, 0, 5, 0, 5, 0, 5, 0, 5, 0 */

/* testing insertionSort */
    print_array(b, sizeof(b) / sizeof(b[0])); /* print: 18, 16, 19, -5, 3, 14, 6, 0 */
    insertion_sort(b, sizeof(b) / sizeof(b[0]));
    print_array(b, sizeof(b) / sizeof(b[0])); /* print: 19, 18, 16, 14, 6, 3, 0, -5 */

/* testing factorial */
    printf("%d\n", factorial(5)); /* print: 120 */

    c[0] = factorial(c[0]);
    c[1] = factorial(c[2]);
    print_array(c, sizeof(c) / sizeof(c[0])); /* print: 24, 120, 5, 3, 1 */
    return 0;
}