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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/Project516/c-calc/llms.txt

Use this file to discover all available pages before exploring further.

Interactive mode is the default way to use c-calc. When you run the binary with no arguments, the program guides you through entering a first number, an operator, and a second number before printing the result. This page walks through each prompt in order and explains what happens when input is invalid or the operator is unrecognized.

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Starting interactive mode

Run the binary with no arguments: 
./c-calc
c-calc checks whether argc == 4. Because no arguments are provided, it falls through to interactive mode and begins prompting immediately.

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Session walkthrough

1

First number prompt

c-calc prints the startup message and then asks for the first operand:
This is a simple calculator written in c
Enter your first number:
Type a number and press Enter. The program reads a double using scanf. If the input cannot be parsed as a number, it prints Invalid input and returns 1 as a fallback value.
2

Operator prompt

After a valid first number is entered, c-calc asks for the operator:
Enter operator:
Type one of the supported operators (+, -, *, /, %) and press Enter. The program reads a single character. If scanf fails, it prints Invalid input.
3

Second number prompt

c-calc then asks for the second operand:
Enter your second number:
Type a number and press Enter. The same scanf validation applies as for the first number.
4

Result

Once all three values are collected, c-calc computes and prints the result formatted to four decimal places:
Result: 50.0000

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Example session

The following shows a complete interactive session multiplying 10 by 5: 
This is a simple calculator written in c
Enter your first number: 10
Enter operator: *
Enter your second number: 5
Result: 50.0000

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Error handling

Invalid input — if scanf cannot parse the value you enter as a number or character, the program prints: 
Invalid input
The calculation still proceeds using the fallback value 1, which may produce an unexpected result. Re-run the program to start over. Unknown operator — if you enter a character that is not one of the five supported operators, c-calc prints: 
Unknown operator
The result is then reported as -1.0000 because the calculate function returns -1 when no case matches. See Supported operators and behavior for the full list.

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