Write a program to convert binary numbers to decimal. The program asks the user for a binary number (0's and 1's) and returns the equivalent in decimalIn order to do so, you need to a) get the length of the string, b) based on the symbol and its position, determine the value in decimal. Binary numbers can be converted to decimals using the expansion formula: n-1 b; = b, * 100 + b, * 101 + by * 102 + .. + bn-1 * 10n-1 Where the binary number is given as: Binary | bn-1 bn-2 ... by bibo Position |ln... 2 1 0 0 n bits The value of each bit(binary digit, depends on its position: Binary bn-1 bn2 T...b2 Tbib Position n-1 nn-2 ... 2 1 0 Decimal Value10n- l10n-1 102 101 100 A) (10 points) Write a function that receives a c-string, and determines if a) is a valid c-string and b) it is a valid binary number (ie. it contains only 0's and 1s). The function will return 1 if the string is valid and 0 otherwise. B) (30 points) Write a function that receives a valid binary c-string (i.e. is a valid c string and contains only 0's and 1s, its length and size and converts to a decimal number. The function will receive only c-strings representing integer numbers >= 0