138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdbool.h>
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#include <ctype.h>
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struct stack{
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char data[100];
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int size;
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}stack;
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///add bracket to stack
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void push(char ch){
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if(stack.size < 100){
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stack.size++;
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stack.data[stack.size] = ch;
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}
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else
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exit(0);
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}
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///if i have opening bracket in stack, then decrement size
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void pop(){
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if(stack.size >= 0)
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stack.size--;
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else
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exit(0);
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}
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///compare brackets
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bool find_pair(char a, char b){
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if(a == '(' && b == ')')
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return true;
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if(a == '{' && b == '}')
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return true;
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if(a == '<' && b == '>')
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return true;
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if(a == '[' && b == ']')
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return true;
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return false;
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}
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///function to find right pair
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char right_pair(char a){
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char b;
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if(a == '(')
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b = ')';
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if(a == '{')
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b = '}';
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if(a == '[')
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b = ']';
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if(a == '<')
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b = '>';
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return b;
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}
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///find the last opening bracket in the stack
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char gettop(){
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return stack.data[stack.size];
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}
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int main(){
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char line[100];
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stack.size = -1;
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printf("Read: ");
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char *x = fgets(line, 100, stdin);
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printf("%s", line);
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int l = strlen(line);
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int i, j = -1, f = -1;;
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char *o_bracket = calloc(l, sizeof(char));
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char *c_bracket = calloc(l, sizeof(char));
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for(i = 0; i < l; i++){
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if(line[i] == '{' || line[i] == '(' || line[i] == '[' || line[i] == '<'){
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push(line[i]);
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j++;
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f++;
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o_bracket[j] = gettop(); //get opening bracket from the stack
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c_bracket[f] = right_pair(o_bracket[j]); //get closing bracket
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}
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if(line[i] == '}' || line[i] == ')' || line[i] == ']' || line[i] == '>'){
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if(stack.size == -1){ //if there is no opening bracket in the stack
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printf("Unexpected closing bracket %c in %d\n", line[i], i);
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return 0;
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}
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else if(!find_pair(gettop(), line[i])){ //if there is another closing bracket
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printf("Crossed bracket %c in %d, expected %c \n", line[i], i, c_bracket[f]);
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return 0;
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}
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else{
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c_bracket[f] = 0; //if closing bracket is correct then reducee array
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f--; //if i didn't find a correct bracket, then keep it in the array
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pop();
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}
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}
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}
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int begin = 0;
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int end = strlen(c_bracket);
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int temp;
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//now i have all missing closing brackets in array
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//flip array
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while(begin < end){
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temp = c_bracket[begin];
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c_bracket[begin++] = c_bracket[--end];
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c_bracket[end] = temp;
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}
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//if program pop all opening brackets from the stack, then stack size must be -1;
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if(stack.size == -1){
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printf("All brackets OK\n");
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}
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//if no, then program didn't find closing bracket
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else {
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printf("Missing closing brackets: %s\n", c_bracket);
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}
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free(o_bracket);
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free(c_bracket);
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return 0;
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}
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