Algorithm :
Scan tokens from left to right
if you find a operator push it into stack
if you find a operand print it and also pop the operator from the top of the stock and print it
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| %{ | |
| char stack[100]; | |
| int tos=0; | |
| void push(char ch); | |
| %} | |
| %% | |
| [a-zA-Z] { printf("%c %c ",yytext[0],stack[--tos]); } | |
| [+\*\/\(\)\-] { push(yytext[0]); } | |
| %% | |
| void push(char ch){ | |
| stack[tos++]=ch; | |
| } | |
| int yywrap(){ | |
| return 1; | |
| } | |
| int main() | |
| { | |
| yylex(); | |
| return 0; | |
| } |
coding hangover 