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new to C, expected expression before 'double' message

This is a discussion on new to C, expected expression before 'double' message within the C Programming forums, part of the General Programming Boards category; i need to ' Write a program to print a table of ex using both a function and the exp() ...

  1. #1
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    Jan 2012
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    new to C, expected expression before 'double' message

    i need to 'Write a program to print a table of ex using both a function and the exp() function from the math.h library, for x = 0 to 1 in steps of 0.1. The program should ask the user what value of n to use, being how many terms in the taylor expansion.' I get the error message 'expected expression before 'double' and dont know what to do!
    Code:
    #include <stdlib.h>
    Code:
    #include <stdio.h>
    #include <math.h>
    
    
        
        double taylor(double x, int n) 
        {
            int i; 
            double sum = 1.0; 
            double term = 1.0; 
            for (i=1; i<=n; i++) 
            {
                term = term * x / i; 
                sum = sum + term;
            } return sum;
            
    }
    
    
    int main()
    
    
    {    
        int a, n;
        double b, c;
    printf("type in an int: ");
        scanf("%d", &n);
        
        for (a=0; a<=10; a++)
        {
            b = a/10.0;
            c = taylor(double b, int n);
        }
        
        printf("%f\t%f\n", b, c);
        
        exit(0);
    }

  2. #2
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    When you pass a parameter to a function, you need not specify its type. Simply remove 'double' and 'int' where you are passing your variables (you still need them when declaring and defining functions though! just not calling them).

    Also, you should not terminate your program with exit(0). Your program will be terminated once control reaches the end of the main function. To return 0 from your main (the 0 in exit(0) is the return value) function simply add 'return 0' to the end.
    jadejones likes this.

  3. #3
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    thank you so much! you can tell im pretty new to this, i was searching the internet for a while on what to do! im such a computing noob Much appreciated!

  4. #4
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    As long as you post brief code that demonstrates your problem clearly, explain what the program should do, and repeat any error messages that you get (all of these which you have already done) then everyone here will be happy to help you.
    stahta01 and iMalc like this.

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