Errors when compiling code.

Hello everyone,

I am very new at C programming and I am following the book from O'Reilly called "Practical C" 3rd Edition.

The exercise at the end of Chapter 1 ask to make a program to print your Name, Social Security number and Date of Birth. This is MY own code I came up with to do this:

Code:

/* This program is designed to produce a Name, Date of Birth and a SS number */ #include <stdio.h> int dob; /* Date of Birth */ int ssn; /* SS Number */ int full_name; /* Full Name */ int main() { dob = 1981; ssn = 047237554; full_name = "John W Doe"; } { printf("Hi, my name is %d.", full_name); printf("I was born on %d.", dob); printf("My SS number is %d.", ssn); return (0); }

When I try to compile the program I get the following error:

Code:

Manuel-Velezs-MacBook-Pro:c_files Manolo$ cc -g -o exercise_1 exercise_1.c exercise_1.c:14:8: error: invalid digit "9" in octal constant exercise_1.c: In function ‘main’: exercise_1.c:15: warning: assignment makes integer from pointer without a cast exercise_1.c: At top level: exercise_1.c:19: error: expected identifier or ‘(’ before ‘{’ token

I feel like I'm missing something really obvious and I'm gonna feel stupid once I can get an idea of what's going on but I love trying to learn this stuff! Thank you in advance for everyones help!

When you start an integer constant with a 0 it is considered to be in octal (base-8) and therefore can only have the digits 0 to 7, inclusive. You must have changed something, though, as that error does not occur with the code you posted. Did you originally have a 0 before the 1981? like 04211981 or something like that? Also, you need to remove the leading zero in your ssn, or change its representation to a string.

full_name is obviously not supposed to be an integer, since "John W Doe" is not an integer; it is a string. For your current purpose, try a char* (a character pointer). And in printing it out with the printf, use %s (for a string) rather than %d (for an integer).

And you need to remove the close-brace, open-brace in the middle of your code. The close brace closes off your main, which you do not want to do at that point.

Ok so I scraped the other code and started over and I still can't get this. I'm sorry for all the obvious errors I might be making I'm just trying to go by the book but I'm not getting these parts that I am messing up. Here is the new code I created:

Code:

/* This program is designed to produce a Name, Date of Birth and a SS number */ #include <stdio.h> /* Desfine Variables */ char first_name; /* First Name of User */ char middle_name; /* Middle Name of User */ char last_name; /* Last Name of User */ int year_born; /* Birth Date */ int current_year; /* Current Year */ int age; /* Age to Date */ int ssn_1; /* First three numbers of your SS */ int ssn_2; /* Middle two numbers of your SS */ int ssn_3; /* Last four numbers of your SS */ int main() { year_born = 1983; current_year = 2012; age = current_year - year_born; first_name = John; middle_name = W; last_name = Doe; ssn_1 = 045; ssn_2 = 68; ssn_3 = 3257; printf("Hello, my name is %s\n%s\n%s", first_name,middle_name,last_name); printf("This year I'm going to %d years old", age); printf("My SS number is %d\n%d\n%d\n", ssn_1,ssn_2,ssn_3); return(0); }

Now I get the following error:

Code:

Manuel-Velezs-MacBook-Pro:c_files Manolo$ cc -g -o exercise_1 exercise_1.c exercise_1.c: In function ‘main’: exercise_1.c:22: error: ‘John’ undeclared (first use in this function) exercise_1.c:22: error: (Each undeclared identifier is reported only once exercise_1.c:22: error: for each function it appears in.) exercise_1.c:23: error: ‘W’ undeclared (first use in this function) exercise_1.c:24: error: ‘Doe’ undeclared (first use in this function) exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’ exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 3 has type ‘int’ exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 4 has type ‘int’ exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’ exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 3 has type ‘int’ exercise_1.c:29: warning: format ‘%s’ expects type ‘char *’, but argument 4 has type ‘int’

I thought by maybe changing the variables around it might work but I guess I'm using them wrong.

Read this link strncpy - C++ Reference

Edited code to show one of the ways to do this; note, I only fixed the string assignment issue in one place.

Code:

/* This program is designed to produce a Name, Date of Birth and a SS number */ #include <stdio.h> #include <string.h> #define MAX_NAME_LENGTH 31 /* Desfine Variables */ char first_name[MAX_NAME_LENGTH + 1]; /* First Name of User */ char middle_name[MAX_NAME_LENGTH + 1]; /* Middle Name of User */ char last_name[MAX_NAME_LENGTH + 1]; /* Last Name of User */ int year_born; /* Birth Date */ int current_year; /* Current Year */ int age; /* Age to Date */ int ssn_1; /* First three numbers of your SS */ int ssn_2; /* Middle two numbers of your SS */ int ssn_3; /* Last four numbers of your SS */ int main() { year_born = 1983; current_year = 2012; age = current_year - year_born; strncpy (first_name,"John",MAX_NAME_LENGTH); /* middle_name = W; last_name = Doe; */ ssn_1 = 045; ssn_2 = 68; ssn_3 = 3257; printf("Hello, my name is %s\n%s\n%s", first_name,middle_name,last_name); printf("This year I'm going to %d years old", age); printf("My SS number is %d\n%d\n%d\n", ssn_1,ssn_2,ssn_3); return(0); }

Reply::

Thank you for your help! I re did it the way you said and make the changes and it works. I have to read up on what you did because in the book we did not get that far in using those things you used in the code but I will study them and make sure I learn them. Again, thank you so much for your help!

Reply 2

Hey I got it to work a different way! I think I was trying to do too much too soon in the previous post I posted above! I did the following and it worked perfect with no errors:

Code:

/* * *Program created to print your Name, Date of Birth and SS Number * */ #include <stdio.h> int ssn1; /* First set of SSN */ int ssn2; /* Second set of SSN */ int ssn3; /* Third set of SSN */ int year1; /* Current Year */ int year2; /* Year Born */ int age; /* Age Turning in Current Year */ int main() { /* * Set up of SSN veriables. */ ssn1 = 145; ssn2 = 23; ssn3 = 3443; /* *Set up of Year veriables. */ year1 = 2012; year2 = 1983; /* *Set up of Age veriable. */ age = year1 - year2; /* *Set up of Print Statements. */ printf("Hello, my name is Manny I. Velez\n"); printf("I was born on November 2nd, %d\n", year2); printf("This year, I'm going to be %d\n", age); printf("My Social Security number is %d %d %d\n", ssn1,ssn2,ssn3); /* *End Program Statement */ return (0); }

But thank you for your help!!! I'm reading on the features you stated above and know it a tiny bit better now in what you did. I know I'll run into this in the near future and at least will have a heads up on it! Thanks!!! :)