1. Understand argc and argv
Yung-Hsiang Lu
Purdue University

2. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }

3. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
an integer as indexes

4. %d means the value of an integer This line prints argc's value
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
%d means the value of an integer
This line prints argc's value

5. argc is the number of arguments it is at least one
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
argc is the number of arguments
it is at least one

6. the first argument is the program's name
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
the first argument is the
program's name

7. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
ind is 0, 1, 2, ... argc - 1

8. and the value of the argument
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
print the index
and the value of the argument

9. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
print an integer

10. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
print a string

11. #include <stdio. h> #include <stdlib
#include <stdio.h> #include <stdlib.h> int main(int argc, char * * argv) { int ind; printf("argc = %d\n", argc); for (ind = 0; ind < argc; ind ++) printf("argv[%d] = %s\n", ind, argv[ind]); } return EXIT_SUCCESS; }
ind is 0, 1, 2, ..., argc - 1
not 1, 2, ..., argc