int ans, guess, random, type, counter, num, i;
char option[20], numb[10], input[5];
 
 
int power(int num)
{
    ans=2;
    if(num==0)
    {
        return(1);
    }    
    if(num<0)
    {
        printf("incorrect input, please input a positive integer:");
        return(0);
    }    
 
    else
        for(i=1; i!=num; i++)
            {
                    return(ans=ans*2);
            }    
    return(0);
} 
 
int main()
{
/*before this there is all the switch case stuff*/
case 1 : 
     	/*powers of 2 calculator*/
printf("please enter a positive integer:\n");
fgets(numb, sizeof(numb), stdin);
sscanf(numb, "%d",&num);
printf("the answer is:%d\n",power(num));
break;
 
ok so the origional was:
case 1 : 
				/*powers of 2 calculator*/
			printf("please enter a positive integer:\n");
            fgets(numb, sizeof(numb), stdin);
            sscanf(numb, "%d", &num);
            ans=2;
            if(num<0)
            printf("incorrect input, please input a positive integer:");
            if(num==0)
            printf("the answer is 1\n");
            for(i=1; i!=num; i++)
            ans=ans*2;
            printf("The answer is %d\n", ans);
			break;