Wednesday, March 24, 2010

Simple C Calculator

Code is compilable for basic integer operations:

x + y

x - y

x * y

x / y

(space reqd between mainline arguments)

Though this code is too simple to share with computer science enthusiasts, but lets build C concepts over a simple snippet:


#include <stdio.h>
typedef struct {
    int operand1;
    int operand2;
    char inp_operator;   
} operation;
void parse_user_input(int arg_index, operation *a, char * mainline_arg);
int string_to_int_conversion(char * string);
int main(int argc, char* argv[])
    int loop_index;
    operation calc; 
    //Extract input digits and end-user's desired operation
    for(loop_index = 1; loop_index <argc; loop_index++)
        //printf(" loop index is %d\n", loop_index);
        //printf("%s\n", argv[loop_index]);
        parse_user_input(loop_index, &calc, argv[loop_index]);
    switch (calc.inp_operator)
    case '+':
        printf("%d\n", (calc.operand1 + calc.operand2));
    case '-':
        printf("%d\n", (calc.operand1 - calc.operand2));
    case '*':
        printf("%d\n", (calc.operand1 * calc.operand2));
    case '/':
        printf("%d\n", (calc.operand1 / calc.operand2));
        printf("Invalid operands entered as %d, %d, %c, exiting without calculation", calc.operand1, calc.operand2, calc.inp_operator);
    return 0;
//Logic for parsing user input storing basic arithmetic operands and operations
void parse_user_input(int arg_index, operation *a, char * mainline_arg)
  if (arg_index == 1)
     a->operand1 = string_to_int_conversion(mainline_arg); 
     //printf("%d\n", a->operand1);
  if (arg_index == 2)
     a->inp_operator = mainline_arg[0]; 
  if (arg_index == 3)
     a->operand2 = string_to_int_conversion(mainline_arg); 
     //printf("%d\n", a->operand2);

//Logic for converting string to decimal if 
//each element entered between 0-9 
int string_to_int_conversion(char * string)
    int converted_integer = 0;
    while ((*string != '\0') && (*string >='0') && (*string <='9') )
        converted_integer = (converted_integer * 10) + (*string -'0');

    return converted_integer;

1.Use Function polymorphism in above C program
2. Introduce floating point arithmetic in the above code


Sandy said...

Could you re-post this inside a PRE tag so that its easier to follow code. Or, you may use the Syntax Highlighter to post the code as it would look like in an IDE.

Pilot-Pooja said...

I have added PRE tag, makes no difference visible to me, Syntax Highlighter does not seem to work with the link provided, only a rar file is downloaded, no installer

Sandy said...

Don't worry, I will get you the code which you can use for your post that will get things in place.

Secondly, Syntax Highlighter is a script that runs to highlight code. It would need to be installed on your blog and then it will start doing its magic. I will send you the details offline on how to set it up, in case you would be interested.

Pilot-Pooja said...

Thanks Sandy, PRE tag now works fine.
Please share the details for installing script on the blog.

sandy said...

You may want to use Sparkle for code highlighting going forth. Let me know if it helps.