Question

How would you implement a stack in C with some initial capacity, but it can grow in size depending on growF. Likewise, how would you implement a stack with some initial capacity that it can grow and shrink in size with growF and shirnkF?

Stack* makeStackG(int cap, float growF){

}

Stack* makeStackGnS(int cap, float growF, float shrinkF) {

}

Answer 1

Below is the C code I hope that i have provided sufficient comments for your better understanding Note that I have done proper indentation but this code is automatically left alligned on this interface

#include<stdio.h>
struct stack
{
    int cap,top,*arr;
};
void push(struct stack*);
void pop(struct stack*);
int getCapacity(struct stack*);
struct stack* createstack(int);
void main()
{
    int choice;
    int temp;
    struct stack *stk;
    stk=createstack(3);
    printf("1.push\n2.pop\n3.capacity\n4.exit\n");
    while(1)
    {
        printf("\nEnter choice: ");
        scanf("%d",&choice);
        switch(choice)
        {
        case 1:
            push(stk);
            break;
        case 2:
            pop(stk);
            break;
        case 3:
            printf("Stack capacity is %d",getCapacity(stk));
            break;
        case 4:
            exit(0);
        }
    }
}
struct stack* createstack(int cap)
{
    struct stack *stk = (struct stack*)malloc(sizeof(struct stack));
    stk->cap = cap;
    stk->top = -1;
    stk->arr=(int *)malloc(sizeof(int)*stk->cap);
   return(stk);
};
int getCapacity(struct stack *stk)
{
    return stk->cap;
}
void push(struct stack *stk)
{
    int data, i;
    int *temp;
    printf("enter data\t");
    scanf("%d",&data);
    if(stk->top==stk->cap-1)    //stack is full
    {
        stk->cap*=2;    //double the capacity
        temp = (int *)malloc(sizeof(int)*stk->cap);
        for(i=0;i<stk->cap/2;i++)
            temp[i] = stk->arr[stk->top];
        stk->arr = temp;
    }
    stk->top++;
    stk->arr[stk->top]=data;
}
void pop(struct stack *stk)
{
    if(stk->top==-1)
        printf("stack is empty\n");
    else
        stk->top--;
}

Below is the screenshot of output

"CAUsers Prakher 1Documentslcltest.exe" 1.push 2.pop 3.capacity 4.exit Enter choice: 1 enter data 10 Enter choice: 1 enter data 20 Enter choice: 3 Stack capacity is 3 Enter choice: 1 enter data 30 Enter choice: 1 enter data 48 Enter choice: 3 Stack capacity is 6 Enter choice: 4 Process returned 0 (8x0) execution time : 22.352 s Press any key to continue.

I have tried to explain it in very simple language and I hope that i have answered your question satisfactorily.Leave doubts in comment section if any.