int ah[size]; //чё там у тя

bool is_par(int val,int n){
for(int i=0;i<=size;i++){
if(i!=n){if(ah[i]==val) return 1;}}
return 0;
}
}

int main(void){
for(int i=0;i<=size;i++){
if(is_par(ah[i],i)) ah[i]/=2;
else ah[i]+=1;
}
return 0;
}

# define BYTESWAP(n) ( \
        (((n)&0x000000ff) << 24) | \
        (((n)&0x0000ff00) << 8 ) | \
        (((n)&0x00ff0000) >> 8 ) | \
        (((n)&0xff000000) >> 24) )

gcc -c -Wall -O2 -fomit-frame-pointer -I/usr/local/include -L/usr/local/lib -funroll-loops xxxxxxx.c
xxxxxxx.c:68: syntax error before `&'
xxxxxxx.c:68: stray '\' in program
xxxxxxx.c:69: stray '\' in program
xxxxxxx.c:70: stray '\' in program
*** Error code 1