LEFT $ Function:

The LEFT $ function in computer programming is used to extract a specified number of characters from the left side of a string. This function takes two arguments: the string from which characters need to be extracted and the number of characters to extract. For example, if we have a string "Hello, World!" and we use the LEFT $ function with 5 as the second argument, it will return "Hello".

Example:
LEFT$("Hello, World!", 5) will return "Hello"

SGN $ Function:

The SGN $ function in computer programming is used to determine the sign of a number. It returns -1 if the number is negative, 0 if the number is zero, and 1 if the number is positive. This function is helpful in mathematical calculations and comparisons where the sign of a number is important.

Example:
SGN$(-5) will return -1
SGN$(0) will return 0
SGN$(10) will return 1

Using these functions in programming can help in manipulating strings and numbers effectively and efficiently.