stack.c

//8

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

typedef struct{
    int*stack;
    int max;
    int top;
}st;

void display(st*p){
    if(p->top==-1){
        printf("STACK EMPTY\n");
        return;
    }
    printf("\nSTACK:\n");
    for(int i=p->top;i>=0;i--){
        printf("%d\n",p->stack[i]);
    }
}

void push(st*p){
    if(p->top==p->max-1){
        printf("STACK OVERFLOW\n");
        return;
    }

    int val;
    printf("Enter the value to insert: ");
    scanf("%d",&val);
    p->stack[++p->top]=val;
}

void pop(st*p){
    if(p->top==-1){
        printf("STACK UNDERFLOW\n");
        return;
    }
    printf("Popped value: %d\n",p->stack[p->top--]);
}

void peek(st*p){
    if(p->top==-1){
        printf("STACK EMPTY\n");
        return;
    }

    printf("TOP OF STACK-> %d\n",p->stack[p->top]);
}

void main(){
    st*p=(st*)malloc(sizeof(st));
    if(p==NULL){
        printf("Memory allocation failed...\n");
        return;
    }

    p->top=-1;
    printf("Enter the maximum capacity of the stack: ");
    scanf("%d",&p->max);

    p->stack=(int*)calloc(p->max,sizeof(int));

    int ch;
    for(;;){
    printf("\nENTER:\n1. To display\n2. To push\n3. To pop\n4. To peek\n0. To EXIT\nEnter your choice from above: ");
    scanf("%d",&ch);

    switch(ch){

        case 1:
        display(p);
        break;

        case 2:
        push(p);
        break;

        case 3:
        pop(p);
        break;

        case 4:
        peek(p);
        break;

        case 0:
        printf("Exiting...\n");
        free(p);
        free(p->stack);
        exit(0);

        default:
        printf("Invalid Choice! Please Enter Again!\n");

    }

    }
}