This is a C program to convert octal number to decimal.

This program takes a octal number as input and converts it into decimal number.

1. Take a octal number as input.

2. Multiply each digits of the octal number starting from the last with the powers of 8 respectively.

3. Add all the multiplied digits.

4. The total sum gives the decimal number.

Here is source code of the C program to Convert Octal to Decimal. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

`/*`

`* C Program to Convert Octal to Decimal`

`*/`

`#include <stdio.h>`

`#include <math.h>`

int main()

`{`

long int octal, decimal = 0;

int i = 0;

printf("Enter any octal number: ");

scanf("%ld", &octal);

while (octal != 0)

`{`

decimal = decimal +(octal % 10)* pow(8, i++);

octal = octal / 10;

`}`

printf("Equivalent decimal value: %ld",decimal);

return 0;

`}`

1. Take the octal number as input and store it in the variable octal.

2. Initialize the variables decimal and i to zero.

3. Obtain the remainder and quotient of the octal number. Multiply the remainder by powers of 8 using function pow(8, i++), add this value to the variable decimal and store it in the variable decimal.

4. Override the variable octal with quotient.

5. Repeat the steps 3 and 4 with the quotient obtained until the quotient becomes zero.

6. Print the variable decimal as output.

Output: Enter any octal number: 67 Equivalent decimal value: 55

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