Thread: Please Improve my code

Hello to every one ....
I'm a Beginner to programming...
I have a folder that contains two sub folders one is "JAVA FILES" and another one is CLASS FILES. I write some java programs and compile it and the output of the compilation it generates the .class file . I want to move the .java file to "JAVA FILES" folder and .class file to the "CLASS FILES" folder.So i write a c program to perform this task My c program code is

Code:

#include <stdio.h>
#include <string.h>

//check the file extension is related to class or java files
int validfile(char * str)
{
    if(strstr(str,".class") || strstr(str,".java"))
    {
    //    printf("Valid extension");
        return 1;
    }

    else
    {
    //    printf("Invalid extension");
        return 0;
    }
    
}

int main(int argc,char *argv[])
{
    FILE *Sourcefile,*Destinationfile;
    char filename[50];
        
    if(validfile(argv[1]) == 1)        
    {
    
    //    Open the source file for reading task
        Sourcefile = fopen(argv[1],"r");

    //    Check the file is opened without error
        if(Sourcefile == NULL)
        {
            printf("file is not opened something problem in opening file");
            return -1;        
        }    
        
        if(strstr(argv[1],".class"))            
        {
            //char filename[20];
            
            strcpy(filename,".//CLASS FILES//");            
            strcat(filename,argv[1]);        
        //      printf("%s",filename);
        }
        else 
        {
            //char filename[20];
            
            strcpy(filename,".//JAVA FILES//");            
            strcat(filename,argv[1]);        
        //      printf("%s",filename);
            
        }
        
        //     create the destination file 
            Destinationfile = fopen(filename,"w");
            
    
        //    Check the file is opened without error
            if(Destinationfile == NULL)
            {
                printf("file is not opened something problem in opening file");
                return -1;        
            }    
            
        //    copy data from source file to destination file
            do                    
            {
                
                int ch = fgetc(Sourcefile);
                if(!feof(Sourcefile))
                    fputc(ch,Destinationfile);
                            
            }    while(!feof(Sourcefile));                
            
            fclose(Sourcefile);
            fclose(Destinationfile);    
            
            remove(argv[1]);    
    }
    
    else
    {    
        printf("File has invalid extensions");
                    
    
    }
    
    return 0;
}

I would move the file to the subfolder by parsing file name to this program via command line argument.please help me to change my simple program to efficient one[that is code written by c professionals]...... [Sorry for my english] Thank you .....