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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
typedef struct ast_node ast_node;
typedef enum op {
ADD = 0,
SUB = 1,
MUL = 2,
DIV = 3,
} op;
typedef struct ast_node {
op operation;
int realLeft;
int realRight;
ast_node *right;
ast_node *left;
} ast_node;
void freeAst(ast_node *head){
if (head->left != NULL)
freeAst(head->left);
if (head->right != NULL)
freeAst(head->left);
free(head);
}
int exec(ast_node *exp){
if (exp->left != NULL){
exp->realLeft = exec(exp->left);
freeAst(exp->left);
exp->left = NULL;
}
if (exp->right != NULL){
exp->realRight = exec(exp->right);
freeAst(exp->right);
exp->right = NULL;
}
if (exp->operation == ADD)
return exp->realLeft+ exp->realRight;
if (exp->operation == SUB)
return exp->realLeft - exp->realRight;
if (exp->operation == MUL)
return exp->realLeft * exp->realRight;
if (exp->operation == DIV)
return exp->realLeft/ exp->realRight;
return 0;
}
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