C 八进制转十进制的程序

#include <stdio.h>
#include <math.h>
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;
}
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: 78
78 in decimal = 116 in octal

#include <stdio.h>
#include <math.h>
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;
}
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: 116
116 in octal = 78 in decimal