Which data structure is used to convert infix notation to postfix notation?

To convert infix notation to postfix notation, a stack is used. The algorithm processes each token from left to right: If the token is an operand, add it directly to the output. If the token is an operator, pop operators from the stack to the output while they have higher or equal precedence, then push the current operator. If the token is a left parenthesis, push it onto the stack. If the token is a right parenthesis, pop operators to the output until a left parenthesis is found. After processing all tokens, pop any remaining operators from the stack to the output. The stack ensures correct operator precedence and handles parentheses efficiently.