#include <stdio.h>
#include <math.h>
// function prototype
int convertDecimalToOctal(int decimalNumber);
int main() {
int decimalNumber;
printf("Enter a decimal number: ");
scanf("%d", &decimalNumber);
printf("%d in decimal = %d in octal", decimalNumber, convertDecimalToOctal(decimalNumber));
return 0;
}
// function to convert decimalNumber to octal
int convertDecimalToOctal(int decimalNumber) {
int octalNumber = 0, i = 1;
while (decimalNumber != 0) {
octalNumber += (decimalNumber % 8) * i;
decimalNumber /= 8;
i *= 10;
}
return octalNumber;
}
Enter a decimal number: 54
54 in decimal = 66 in octal
#include <stdio.h>
#include <math.h>
// function prototype
long long convertOctalToDecimal(int octalNumber);
int main() {
int octalNumber;
printf("Enter an octal number: ");
scanf("%d", &octalNumber);
printf("%d in octal = %lld in decimal", octalNumber, convertOctalToDecimal(octalNumber));
return 0;
}
// function to convert octalNumber to decimal
long long convertOctalToDecimal(int octalNumber) {
int decimalNumber = 0, i = 0;
while(octalNumber != 0) {
decimalNumber += (octalNumber%10) * pow(8,i);
++i;
octalNumber/=10;
}
i = 1;
return decimalNumber;
}
Enter an octal number: 63
63 in octal = 51 in decimal
#include <stdio.h>
#include <math.h>
// function prototypes
int checkOctal(int);
long long convertOctalToDecimal(int);
int main() {
int octalNumber;
int condition;
// repeat loop as long as user
// gives a non-octal number
do {
printf("Enter an octal number: ");
scanf("%d", &octalNumber);
// check if number is octal
condition = checkOctal(octalNumber);
if (!condition) {
printf("%d is not an octal number!\n", octalNumber);
}
} while (condition == 0);
printf("%d in octal = %lld in decimal", octalNumber, convertOctalToDecimal(octalNumber));
return 0;
}
// function to check octal number
int checkOctal(int octalNumber) {
int remainder;
// check each digit of input number
while(octalNumber != 0) {
remainder = octalNumber % 10;
// return 0 if a digit is 8 or 9
if (remainder >= 8) {
return 0;
}
octalNumber/= 10;
}
// return 1 if number is octal
return 1;
}
// function to convert octalNumber to decimal
long long convertOctalToDecimal(int octalNumber) {
int decimalNumber = 0, i = 0;
while(octalNumber != 0) {
decimalNumber += (octalNumber%10) * pow(8,i);
++i;
octalNumber/=10;
}
i = 1;
return decimalNumber;
}
Enter an octal number: 69
69 is not an octal number!
Enter an octal number: 36
36 in octal = 30 in decimal