Command Line Arguments

Usually we write main like this

void main()

You’ll often see it written like this instead

int main(int argc, char* argv[])

This allows us to give our program inputs/arguments. The second input, argv stores the name of the program and the values of the arguments while the first input tells us how many we received.

We give a program inputs on the command line by following the ./programName with the inputs. If we wanted to give the program three inputs, 5, 5.5 and the string “hello world” we could type:

./programName 5 5.5 "hello world"

In this case argc==4 because there is one program and three arguments. argv is an array of strings (char* s) with the following values

Note that the numeric inputs are stored as strings, not ints or floats. We can convert strings to numbers using the two functions

int   atoi(char *s) // convert string to int
float atof(char *s) // convert string to float

Eclipse

Arguments in Eclipse

To enter arguments in Eclipse