Question

#include <stdio.h>
#include <math.h>

long int input;
long int base, exponent;

void convert(long int x,long int y)
{
    input = x;
    base = y;

    while (input > 0){
        exponent = floor(log(input)/log(base));
        input = input - pow(base, exponent);
    }
}

int main(void){
    scanf("%d", &input);
    scanf("%d", &base);
    convert(input, base);
}

I was trying to compile the code above to see if I can convert decimal into different bases, but I get the following error:

assignment2.c(14): error C2143: syntax error : missing ';' before 'type'

I have been struggling for hours, but I have no idea what this is referring to. How can I fix this?

EDIT: this is the whole message

1>------ Build started: Project: assignment2, Configuration: Debug Win32 ------
1>Build started 2012-04-27 오후 5:45:10.
1>InitializeBuildStatus:
1>  Touching "Debug\assignment2.unsuccessfulbuild".
1>ClCompile:
1>  assignment2.c
1>c:\users\조화수\documents\visual studio 2010\projects\assignment2\assignment2\assignment2.c(14): error C2143: syntax error : missing ';' before 'type'
1>  assign2.c
1>c:\users\조화수\documents\visual studio 2010\projects\assignment2\assignment2\assign2.c(13): warning C4244: '=' : conversion from 'double' to 'long', possible loss of data
1>c:\users\조화수\documents\visual studio 2010\projects\assignment2\assignment2\assign2.c(14): warning C4244: '=' : conversion from 'double' to 'long', possible loss of data
1>c:\users\조화수\documents\visual studio 2010\projects\assignment2\assignment2\assign2.c(19): warning C4996: 'scanf': This function or variable may be unsafe. Consider using scanf_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
1>          c:\program files\microsoft visual studio 10.0\vc\include\stdio.h(304) : see declaration of 'scanf'
1>c:\users\조화수\documents\visual studio 2010\projects\assignment2\assignment2\assign2.c(20): warning C4996: 'scanf': This function or variable may be unsafe. Consider using scanf_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
1>          c:\program files\microsoft visual studio 10.0\vc\include\stdio.h(304) : see declaration of 'scanf'
1>  Generating Code...
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:02.98
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

pow and log expect double or float. With a cast it works for me:

exponent = floor(log((double)input)/log((double)base));
input = input - pow((double)base, (double)exponent);

Initially I got an error stating that the compiler couldn’t resolve an ambiguity between various oveloads (on VS 2008)