1 // Reads an integer from stdin and prints it 2 // on stdout in binary base. 3 // only for numbers below 128; 4 5 #include <stdio.h> 6 #include <stdlib.h> 7 8 #define MAX_LEN 8 9 #define ERR_MSG_NEG "Err: invalid number!" 10 11 int main ( void ) { 12 13 int i, num; 14 char buffer[MAX_LEN]; 15 // 0000 0000 16 int bin[MAX_LEN] = {0,0,0,0,0,0,0,0}; 17 18 if(fgets(buffer, MAX_LEN, stdin) == NULL) 19 return 1; 20 21 // Converts the input str to int, if the number 22 // is negative or greater than 128, puts an 23 // error message on stderr; 24 if((num = atoi(buffer)) < 0 || num > 128) { 25 fprintf(stderr, ERR_MSG_NEG"\n"); 26 return 1; 27 } 28 29 // Converts num to binary base by dividing it 30 // by 2 until its zero, the rest of the division 31 // is stored in every itineration in bin[]; 32 for(i = 0; num != 0; i++) { 33 if((num % 2) == 1) { 34 bin[i] = 1; 35 } else { 36 bin[i] = 0; 37 } 38 num = (num / 2); 39 } 40 41 // This part print bin in reverse order because 42 // the previous algorithm stores the values in 43 // reverse order; 44 for(i = 7; i >= 0; i--) { 45 if(i == 3) 46 putchar(' '); 47 48 printf("%d", bin[i]); 49 } 50 51 putchar('\n'); 52 return 0; 53 }
