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  1. #include<iostream>
  2.  
  3. using namespace std;
  4.  
  5. const char input[] = "9-5*2";
  6. int index = 0;
  7. char LookAhead = input[index];
  8.  
  9. void Match(char newChar);
  10. void Factor();
  11. void Rest_();
  12. void Rest();
  13. void Term();
  14. void Expression();
  15.  
  16.  
  17. int main(){
  18.     Expression();
  19.     return 0;
  20. }
  21.  
  22. void Match(char newChar){
  23.     if(newChar == LookAhead){
  24.         index++;
  25.         LookAhead = input[index];
  26.     }
  27. }
  28.  
  29. void Expression(){
  30.     Term();
  31.     Rest();
  32. }
  33.  
  34. void Term(){
  35.     Factor();
  36.     Rest_();
  37. }
  38.  
  39. void Rest(){
  40.     if(LookAhead == '+'){
  41.         Match('+');
  42.         Term();
  43.         cout << '+';
  44.         Rest();
  45.     }else if(LookAhead == '-'){
  46.         Match('-');
  47.         Term();
  48.         cout << '-';
  49.         Rest();
  50.     }else{
  51.  
  52.     }
  53. }
  54.  
  55. void Rest_(){
  56.     if(LookAhead == '*'){
  57.         Match('*');
  58.         Factor();
  59.         cout << '*';
  60.         Rest_();
  61.     }else if(LookAhead == '/'){
  62.         Match('/');
  63.         Factor();
  64.         cout << '/';
  65.         Rest_();
  66.     }else{
  67.  
  68.     }
  69. }
  70.  
  71. void Factor(){
  72.     if(isdigit(LookAhead)){
  73.         cout << LookAhead;
  74.         Match(LookAhead);
  75.     }
  76. }
Success #stdin #stdout 0s 4396KB
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Standard input is empty
stdout
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952*-
https://ideone.com/zl7zKd
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
public

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