how to create a struct in C
problem
You wish to represent a custom data type in your C program. In this post we will see how to represent a student object. A student is made of few pieces of information like a name, surname, age, etc.
SOLUTION
In C, we can use struct keyword to create a custom structure of data which acts as a data type.
struct student {
char name[25];
char surname[25];
int age;
};
Above, we just created a new struct to represent a student in our program that will have 3 fields:
- name
- surname
- age
Now, let’s add it to a main program and initialize a student.
#include <stdio.h>
#include <string.h>
struct student {
char name[25];
char surname[25];
int age;
};
int main() {
struct student joe;
//assign values
strcpy(joe.name, "Joe");
strcpy(joe.surname,"Doe");
joe.age = 18;
//print values
printf("%s, %s, %d\n", joe.surname, joe.name, joe.age);
return 0;
}
At line 12, we declare a new variable of data type (struct student) and then we initialize each field with a value.
Note here that the name and surname are not assignable so we need to use the strcpy function to assign them string values.
At line 20 we can simply print each field by retrieving it using the dot notation.
compiling
In this example, I will compile it using the gcc in the terminal:
gcc student_struct.c
running
./a.out
This is the output in Linux, Mac operating systems, in Windows should be the .exe file. You can refer to their documentation.
output
conclusion
In this post we saw how we can create a data type of our favor, in particular a student that has a name, surname and age. It can easily be extended and have an email, telephone number, gpa. We also saw how to use the dot notation and assign values and also retrieve them for printing.
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Ellion
Professional IT consultant, writer, programmer enthusiast interested in all sorts of coding.
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