>145
void btox(char *x, char *b)
{
int len, xch, i, j;
len = strlen(b);xch=0;
for(i=0;i<len%4;i++){
xch <<= 1;xch |= b[i]-(b[i]>9?'a':'0');
}
x[i/4]=xch+(xch>9?'a':'0');
while(i<len){
xch = 0;
for(j=0;j<4;j++){
xch <<=1;xch |=b[i]-'0';i++;j++;
}
x[i/4]=xch+(xch>9?'a':'0');

}

void xtob(char *b, char *x)
{
int len, xch, i, j;
len = strlen(x);len *= 4;i=0;
while(x[i] != '\0'){
xch = x[i]-(x[i]>9?'a':'0');
b[4*i]=!!(xch & 0x8)+'0';
b[4*i+1]=!!(xch & 0x4)+'0';
b[4*i+2]=!!(xch & 0x2)+'0';
b[4*i+3]=!!(xch & 0x1)+'0';
}
b[4*i] = '\0';
}