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#include <stdio.h>
#include <stdbool.h>
#define STACK_SIZE 10
struct stack {
int data[STACK_SIZE];
int top;
};
bool stack_empty(struct stack *S)
{
if (S->top)
return false;
else
return true;
}
/*
* Push an element to the top of the stack
* - Return the element pushed in case of success
* - Return 0 otherwise
*/
int stack_push(struct stack *S, int value)
{
if (S->top == (STACK_SIZE - 1)) {
printf("Stack full, avoiding overflow\n");
return 0;
}
S->top++;
S->data[S->top] = value;
printf("Last element into stack: %d\n", S->data[S->top]);
return value;
}
int stack_pop(struct stack *S)
{
int ret = 0;
if (S->top == -1) {
printf("Stack empty, avoiding underflow\n");
return 0;
}
ret = S->data[S->top];
S->top--;
return ret;
}
void print_stack(struct stack *S)
{
int i;
printf("Elements into stack: %d\n", S->top + 1);
if (S->top < 0) {
printf("Stack is empty\n");
return;
}
printf("Pos | Val");
for (i = 0; i <= S->top; i++)
printf("\n %d | %d", i, S->data[i]);
printf(" <-- TOP\n");
}
void debug_stack(struct stack *S)
{
int i;
printf(" Stack Pointer is: %d\n", S->top);
for (i = 0; i < STACK_SIZE; i++)
printf("Position: %d - Value: %d\n", i, S->data[i]);
}
int main(void)
{
/* Initialize the stack and all its elements to 0 */
struct stack mystack;
int i = STACK_SIZE;
char cmd;
mystack.top = -1; /* Stack is empty */
for (i = 0; i < STACK_SIZE; i++)
mystack.data[i] = 0;
while (1) {
int val = 0;
printf("Select option (h for help): \n");
scanf(" %c", &cmd);
switch (cmd) {
case 'a':
printf(" Push value: ");
scanf(" %d", &val);
stack_push(&mystack, val);
break;
case 'o':
printf("Popping stack\n");
stack_pop(&mystack);
break;
case 'p':
print_stack(&mystack);
break;
case 'd':
debug_stack(&mystack);
break;
case 'q':
return 0;
default:
printf("Invalid entry, please use:\n");
printf("a - Push value to the stack\n");
printf("o - Pop value from the stack\n");
printf("p - Print the whole stack\n");
printf("d - Debug stack, print all elements\n");
printf(" into the stack array even beyond TOP\n");
printf("q - Exit stack fun\n");
}
}
return 0;
}
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