How can I create a program that allows the user to enter a matrix of any size and replaces only the negative values in the matrix with -100?

Im a beginner at matlab and I can't solve this simple problem. I know a forloop is involved but I am still unsure how to do this.

Answer 1

[Adam]

x( x < 0 ) = -100;

will replace negative values of x with -100. Allowing a user to create a matrix depends how you want to do it. Either a GUI or just on command line.

For loops shouldn't be anywhere near this problem though!