C program help, if there are any questions feel free to ask...

Write a C program with a function that replaces up to the first n given characters in the text with a new character, and returns the number of replacements. If the number of repetitions n is negative, all predefined symbols are replaced with a new one. The function must have the following parameters: text, old symbol, new symbol, repeats number. Select the correct data types for the parameters and function.