Binary Patch Filesizer

#include <stdio.h>

int main(int argc, char *argv[])
{
    FILE *input;
    FILE *temp;
    FILE *output;
    long fs=0;
    char inbyte='\0';
    long count=0;
    char name[512];
    char outstring[512];
    int add=0;
    long insize=0;
    long sizecount=0;
    int d=0;

    if ( ( input=fopen(argv[1],"rb") ) == NULL )
    {
        printf("Input file not found\n");
        exit(-1);
    }

    fseek(input,0L,SEEK_END);
    insize=ftell(input);
    fseek(input,0L,SEEK_SET);

    output=fopen("../tempout2","wb");

    while ( sizecount < insize )
    {
        inbyte='\0';
        fread(&inbyte,1,1,input);
        sizecount++;
        count=0;

        if ( inbyte == 'A' )
        {
            add=1;
        }else{
            add=0;
        }

        while ( inbyte != 32 )
        {
            inbyte='\0';
            fread(&inbyte,1,1,input);
            sizecount++;
        }

        while ( ( inbyte != '\n' ) && ( ! feof(input) ) )
        {
            inbyte='\0';
            fread(&inbyte,1,1,input);
            sizecount++;
            name[count]=inbyte;
            count++;
        }name[count-1]='\0';

        if ( ( temp=fopen(name,"rb") ) == NULL ){
            printf("Target file not found\n");
            exit(-2);
        }
        fseek(temp,0l,SEEK_END);
        fs=ftell(temp);
        fclose(temp);

        for(d=0;d<512;d++)
            outstring[d]='\0';

        if ( add )
        {
            printf("Writing Line \"Add %d %s\"\n",fs,name);
            sprintf(outstring,"Add %d %s\n\0",fs,name);
        }else{
            printf("Writing Line \"Update %d %s\"\n",fs,name);
            sprintf(outstring, "Update %d %s\n\0",fs,name);
        }

        fwrite(&outstring,strlen(outstring),1,output);

    }

    fclose(input);
    fclose(output);
}