Base Convertor

#include <stdio.h>

int main(int argc, char *argv[]){
    if(argv[1] == NULL){
        printf("\nEnter an argument to the program!\n");
        exit(8);
    }
    int in;
    short i, j; //iterator
    char b[12];
    if(sscanf( argv[1], "%d", &in ) == 1);
    else{
        printf("Enter an integer for the argument!\n");
        exit(8);
    }
    //only have to calculate binary and 32 bit, the rest is automatic!
    for(i = 11; i >= 0; i--){
        if((1 << i) & in)
            b[11 - i] = '1';
        else
            b[11 - i] = '0';
    }
    b[12] = 0;
    char b32[32]={"0123456789abcdefghijklmnopqrstuv"};
    i = j = 0; // reset iterators
    char b32result[32]; // the final conversion
    while(in){
        b32result[i] = b32[in%32];
        in = in/32;
        i++;
    }
    //notice the fact you can use %d, %x %o for decimal, hex and octal automatically.
    printf("\nDecimal: %d\nBinary: %s\nOctal: %o\nHex: %x\nBase32: %s\n", in, b, in, in, b32result);
    return 0;
}