C Stack Program Using Array

A stack follows the rule “last in, first out” (LIFO). The last item which is pushed is the first one to come out, like a pile of plates. Here we make a stack with an array.

#include <stdio.h>

#define MAX 5

int stack[MAX];
int top = -1;

void push(int value) {
    if (top == MAX - 1) {
        printf("Stack overflow\n");
        return;
    }
    stack[++top] = value;
}

int pop(void) {
    if (top == -1) {
        printf("Stack underflow\n");
        return -1;
    }
    return stack[top--];
}

int peek(void) {
    return (top == -1) ? -1 : stack[top];
}

int main(void) {
    push(10);
    push(20);
    push(30);

    printf("Top element: %d\n", peek());
    printf("Popped: %d\n", pop());
    printf("Popped: %d\n", pop());
    printf("Top element: %d\n", peek());

    pop();
    pop();     // stack is empty now
    return 0;
}

Output:

How it works

• top is the index of the last item. It is -1 when the stack is empty.
• push() increases top and stores the value. pop() returns the value and decreases top.
• We check top before each operation, to avoid overflow (full stack) and underflow (empty stack).

• Previous Code
• Next Code

---

Tutorials
No Content Found.

Exercises & Assignments
No Content Found.

Interview Questions & Answers
No Content Found.