Question

Implement stack in C

Struct:

struct patients{
int id;
int severity;
char *firstName;
char *lastName;
char *state;
int time_spent;
};

Given Array: struct patients* patientsArray[4] = {&p1, &p2, &p3, &p4};

Create two functions one for pushing this array to the stack and one for popping the variables such as p1 p2 p3 p4 by its ID

Answer 1

#include <stdio.h>

#include <stdlib.h>

struct patients

{

int id;

int severity;

char *firstName;

char *lastName;

char *state;

int time_spent;

};

struct Stack

{

int top;

unsigned capacity;

struct patients* patients;

};

struct Stack* createStack(unsigned capacity)

{

struct Stack* stack = (struct Stack*)malloc(sizeof(struct Stack));

stack->capacity = capacity;

stack->top = -1;

stack->patients = (struct patients*)malloc(stack->capacity * sizeof(struct patients));

return stack;

}

int isFull(struct Stack* stack)

{

return stack->top == stack->capacity - 1;

}

int isEmpty(struct Stack* stack)

{

return stack->top == -1;

}

void push(struct Stack* stack, struct patients pat)

{

if (isFull(stack))

return;

stack->patients[++stack->top] = pat;

printf("%s %s pushed to stack\n", pat.firstName, pat.lastName);

}

int pop(struct Stack* stack)

{

int id;

if (isEmpty(stack))

id = -1;

else

id = stack->patients[stack->top--].id;

return id;

}

int main(void)

{

struct patients p1;

p1.id = 178;

p1.severity = 4;

p1.firstName = "John";

p1.lastName = "Smith";

p1.state = "California";

p1.time_spent = 45;

struct patients p2;

p2.id = 139;

p2.severity = 7;

p2.firstName = "Mary";

p2.lastName = "Jane";

p2.state = "Texas";

p2.time_spent = 23;

struct patients p3;

p3.id = 199;

p3.severity = 2;

p3.firstName = "Ann";

p3.lastName = "Doe";

p3.state = "Florida";

p3.time_spent = 33;

struct patients p4;

p4.id = 167;

p4.severity = 5;

p4.firstName = "Ralph";

p4.lastName = "Bush";

p4.state = "Hawaii";

p4.time_spent = 55;

struct Stack* stack = createStack(10);

push(stack, p1);

push(stack, p2);

push(stack, p3);

push(stack, p4);

printf("Patient id %d popped from stack\n", pop(stack));

return 0;

}

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