判斷任意數字是否是回文數

void main() 
{ 
     long num,smallnum; 
     scanf("%d",&num); 
     smallnum = num; 
     int start=1; 
     int count=0; 
     do{ 
         start*=10; 
         count++; 
     }while(num%start!=num); 
    printf("本數是%d位\n",count); 
    int i; 
    int yes=1; 
    if(count%2==0){ 
        yes=0; 
    } 
    int loopcount = count/2; 
    int innercounter=1; 
    int bigsum=1; 
    int smallsum=1; 
    for(i=1;i<=loopcount;i++){ 
        smallsum=1; 
        for(innercounter=1;innercounter<=i;innercounter++){ 
            smallsum = smallsum*10; 
        } 
        bigsum=1; 
        for(innercounter=1;innercounter<=(count-i);innercounter++){ 
            bigsum = bigsum*10; 
        } 
        int small = smallnum%(smallnum/10); 
        smallnum =  smallnum/=10; 
 
        int big = num/bigsum; 
        num = num%bigsum; 
        if(big!=small){ 
            yes=0; 
            break; 
        } 
    } 
    if(yes==1){ 
         printf("此數是回文數."); 
    }else{ 
         printf("此數不是回文數."); 
    } 
} 

摘自 張仁陽專欄