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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4.  
  5. int *stackbase;
  6. int *stack;
  7. int stack_size;
  8.  
  9. void stackerr(char* str)
  10. {
  11.     printf("%s\n", str);
  12.     exit(999);
  13. }
  14.  
  15. void init_stack(int smax)
  16. {
  17.     stackbase = (int *)malloc(smax * sizeof(int));
  18.     if (stackbase == NULL)
  19.     {
  20.         stackerr("init error");
  21.     }
  22.     stack = stackbase;
  23.     stack_size = smax;
  24. }
  25.  
  26. void extend_stack(void)
  27. {
  28.     int *p, new;
  29.     new = stack_size * 2;
  30.     p = (int *)realloc(stackbase, new * sizeof(int));
  31.     if (p == NULL)
  32.     {
  33.         stackerr("extend error");
  34.     }
  35.     stack = p + (stack - stackbase);
  36.     stackbase = p;
  37.     stack_size = new;
  38. }
  39.  
  40. void print_stack(void)
  41. {
  42.     int *p = stack;
  43.     int n = 0;
  44.     while (p > stackbase)
  45.     {
  46.         p--;
  47.         printf("%d: %d\n", n, *p);
  48.         n++;
  49.     }
  50. }
  51.  
  52. void push(int x)
  53. {
  54.     if (stack >= stackbase + stack_size)
  55.     {
  56.         extend_stack();
  57.     }
  58.     *stack = x;
  59.     stack++;
  60. }
  61.  
  62. int pop(void)
  63. {
  64.     if (stack <= stackbase)
  65.     {
  66.         stackerr("Underflow");
  67.     }
  68.     stack--;
  69.     return *stack;
  70. }
  71.  
  72. void calc(int *a, int c)
  73. {
  74.     int x;
  75.     int y;
  76.     int i;
  77.     int n;
  78.     for (i = 0; i < c; i++)
  79.     {
  80.         n = a[i];
  81.         if (n == -10000)
  82.         {
  83.             y = pop();
  84.             x = pop();
  85.             push(x + y);
  86.         }
  87.         else if (n == -10001)
  88.         {
  89.             y = pop();
  90.             x = pop();
  91.             push(x * y);
  92.         }
  93.         else if (n == -10002)
  94.         {
  95.             printf("%d\n", pop());
  96.             break;
  97.         }
  98.         else
  99.         {
  100.             push(n);
  101.         }
  102.     }
  103. }
  104.  
  105. int main(int argc, char* argv[])
  106. {
  107.     int i;
  108.     char* arg;
  109.     int x;
  110.     int y;
  111.  
  112.     init_stack(1);
  113.     for (i = 1; i < argc; i++)
  114.     {
  115.         arg = argv[i];
  116.         if (strcmp(arg, "+") == 0)
  117.         {
  118.             y = pop();
  119.             x = pop();
  120.             push(x + y);
  121.         }
  122.         else if (strcmp(arg, "x") == 0)
  123.         {
  124.             y = pop();
  125.             x = pop();
  126.             push(x * y);
  127.         }
  128.         else if (strcmp(arg, "p") == 0)
  129.         {
  130.             printf("%d\n", pop());
  131.         }
  132.         else
  133.         {
  134.             push(atoi(arg));
  135.         }
  136.     }
  137.  
  138.     return EXIT_SUCCESS;
  139. }
  140.  
Not running #stdin #stdout 0s 0KB
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https://ideone.com/N3MeXA
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

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