rpn

Stacks, queues, trees32

Objective

Build a postfix calculator: read a single argument containing integers and operators separated by spaces, evaluate it stack-style, and print the final value.

Steps

The program receives exactly one argument: a space-separated sequence of tokens.
Each token is either a base-10 integer or one of the operators +, -, *, /, %.
Process tokens left to right. Push integers on a stack. For an operator, pop the top value as b, then the next as a, and push the result of a OP b.
When the input ends, the stack must contain exactly one value: print it followed by a newline.
If the argument count is wrong, an unknown token is encountered, an operator finds fewer than two operands, the stack does not end with exactly one value, or a division/modulo by zero occurs, print only Error followed by a newline.

examples

$ ./rpn "3 4 +"

$ ./rpn "5 1 2 + 4 * + 3 -"

$ ./rpn "5 0 /"

Error

Constraints

Expected files

rpn.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments yields Error

02Single integer is its own result

03Basic addition

04Basic multiplication

05Operand order matters for subtraction

06Subtraction producing a negative result

07Modulo operator

08Combined expression with nested precedence

09Division by zero is rejected

10Modulo by zero is rejected

11Final stack must contain exactly one value

12Operator without enough operands

rpn

Objective

Build a postfix calculator: read a single argument containing integers and operators separated by spaces, evaluate it stack-style, and print the final value.

Steps

The program receives exactly one argument: a space-separated sequence of tokens.
Each token is either a base-10 integer or one of the operators +, -, *, /, %.
Process tokens left to right. Push integers on a stack. For an operator, pop the top value as b, then the next as a, and push the result of a OP b.
When the input ends, the stack must contain exactly one value: print it followed by a newline.
If the argument count is wrong, an unknown token is encountered, an operator finds fewer than two operands, the stack does not end with exactly one value, or a division/modulo by zero occurs, print only Error followed by a newline.

examples

$ ./rpn "3 4 +"

$ ./rpn "5 1 2 + 4 * + 3 -"

$ ./rpn "5 0 /"

Error

Constraints

Expected files

rpn.c

Allowed functions

write

rpn

Stacks, queues, trees32

Objective

Build a postfix calculator: read a single argument containing integers and operators separated by spaces, evaluate it stack-style, and print the final value.

Steps

The program receives exactly one argument: a space-separated sequence of tokens.
Each token is either a base-10 integer or one of the operators +, -, *, /, %.
Process tokens left to right. Push integers on a stack. For an operator, pop the top value as b, then the next as a, and push the result of a OP b.
When the input ends, the stack must contain exactly one value: print it followed by a newline.
If the argument count is wrong, an unknown token is encountered, an operator finds fewer than two operands, the stack does not end with exactly one value, or a division/modulo by zero occurs, print only Error followed by a newline.

examples

$ ./rpn "3 4 +"

$ ./rpn "5 1 2 + 4 * + 3 -"

$ ./rpn "5 0 /"

Error

Constraints

Expected files

rpn.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments yields Error

02Single integer is its own result

03Basic addition

04Basic multiplication

05Operand order matters for subtraction

06Subtraction producing a negative result

07Modulo operator

08Combined expression with nested precedence

09Division by zero is rejected

10Modulo by zero is rejected

11Final stack must contain exactly one value

12Operator without enough operands