Thread: Need help with C

Hey I'm suppose to make a calculator for one of my assignments I'm just having this annoying problem and can't get it fixed.

I'm trying to use and if-else statement but the else portion keeps executing regardless. please help. I'm not asking you to do my homework for me just correct syntax.

thanks

Code:

#include <stdio.h>#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>


double main(void)
{
   double result = 0.0, num1; char operator, end;
   
   
   printf("Calculator is on.\n\n");
   
   
   do {
   
    printf("Enter an operator symbol:\n");
    scanf("%c",&operator);
    if(operator == '+'){
        scanf("%lf",&num1); 
        result = result + num1;
        printf("%lf",result);}
    if(operator == '-'){
        scanf("%lf",&num1); 
        result = result - num1;
        printf("%lf",result);}
    if(operator == '*'){
        scanf("%lf",&num1); 
        result = result * num1;
        printf("%lf",result);}
    if(operator == '/'){
        scanf("%lf",&num1); 
        result = result / num1;
        printf("%lf",result);}
    else{
        printf("UnknownOperatorException is thrown\n");}
        
    }while(end!='r' ||end!='R');
    
    
   return 0;
   }

Also would i have to put a getchar statement for the while statement to end or can i just move down the while statement after the scanf statement and input 'operator' instead of 'end'

main has to return an int (not a double).

Your scanf call with the %c format should have a space before the %c:

Code:

    scanf(" %c",&operator);

Your printf's should use the format %f, not %lf (although scanf does need %lf).

You need to use "else if". I.e.:

Code:

    if(operator == '+'){
        scanf("%lf",&num1); 
        result = result + num1;
        printf("%f",result);
    }
    else if(operator == '-'){
        scanf("%lf",&num1); 
        result = result - num1;
        printf("%f",result);
    }
    //etc.

Your end condition should use && not ||.

And your brace placement is idiotic. It's hard to read, which defeats the purpose.