Question

Implement a funcion addNumber() in C that takes a pointer to the array and adds a number to the array if the number is not already there.

function protoype: void addNumber(int **arrayPtr, int number ,int *size);

Also implement a removeNumber() function that takes a pointer to the array, a nymber, and removes the number if it is present in the array. If the number is removed, the array shrinks.

function prototype: void removeNumber(int **arrayPtr, int number, int *size);

Answer 1

This definition is not correct to for function that pass array to function as pointer

void addNumber(int **arrayPtr, int number ,int *size); - wrong

correct is

void addNumber(int *arrayPtr, int number ,int *size)

#include <stdio.h>
#include <stdbool.h>

void addNumber(int *arrayPtr, int number ,int *size){
int n=size;
int ar[n+1];
bool isPresent=false; //flag to see if element present
for(int i=0;i<n;i++){
if(arrayPtr[i]!=number){ //if element not present
isPresent=true; //set flag true
break;
}
}
n=n+1; //increse the size of array
for(int i=0;i<n-1;i++){
ar[i]=arrayPtr[i]; //copy element to temp array
}
ar[n-1]=number; //add element at last
arrayPtr=ar; //copy temp array to original array
for(int i=0;i<n;i++){
printf("%d,",arrayPtr[i]); //print array
}
printf("\n");
}
void removeNumber(int *arrayPtr, int number ,int *size){
int n=size;
int ind=-1;

for(int i=0;i<n;i++){
if(arrayPtr[i]==number){ //if number present
ind=i; //store index
break;
}
}

for(int i=ind;i<n-1;i++){ //from that index , shift all element backword by one
arrayPtr[i]=arrayPtr[i+1];
}

for(int i=0;i<n-1;i++){ //test record
printf("%d,",arrayPtr[i]);
}
}
//driver function to test
int main()
{
int ar[]={1,2,3,4,5};
addNumber(ar,9,5);
removeNumber(ar,1,5);

return 0;
}

output

1,2,3,4,5,9,
2,3,4,5,