Chapter 13 explained the array treated bringing two or more variables of the same type together.
However, I occasionally want to treat a different type collectively according to circumstances.
Moreover, distinguishing by the name might be more convenient to distinguish each element by the number.

For instance, I want to preserve the result of student's body measurement at the school.
As for each student, the data of the class, the school year, the attendance number, the name, the height, and weight, etc. is necessary.
When this is obediently prepared by the variable, it becomes the following.

 int year; /* school year */  Int clas;/* class */  Int number;/* attendance number */  Char name[64];/* name */  Double stature;/* height */  Double weight;/* Weight */

Clas Though class is a correct spelling
In C++ Because class dares to be a reserved word It makes it to clas.
If you do not like it Group might be acceptable.

Naturally, this functions enough as student's data.
However, though these data is all the relating data
Because each one is declared as another variable, it is not so comprehensible.

As a method of handling collectively in such a case in one of the variable of two or more different types
The function of structure is prepared.

[   Structure   ]
Type made bringing two or more different types together

 School year..class..attendance..number..name..height..weight. 
};

[   Structure tag name   ]
Name of made structure deflecting.
Note that it is not a type strictly name.

Though the type of the novel structure can be made by doing in this manner
It is to merely declare the type, it is not possible to actually use it being possible this to hold.
It is necessary to declare the variable of the type of the structure to actually use it.
Do as follows to declare the variable of the type of the structure.

 
struct student data;

[   C++   ]
In C++ that is the extended version of C language
Even if struct is not applied, the structure variable can be declared.
Most : a present compiler because it is for C++.
Even if struct is not applied, it is possible to declare.

 School year..class..attendance..number..name..height..weight. 
};

int main(void) 
{
	struct student data; 
	return 0; 
}

In the preceding clause, the declaration of the structure tag and the structure variable though it explained
It is not significant to no use actually no matter how it declares.

The structure variable has all types declared in the structure tag that became an origin.
When arranging it though the variable of the same type was distinguished according to the number
In the structure variable, distinguish all elements according to the name regardless of the type.
Do as follows to access one element of the structure variable.

構造体変数名.要素名

 
#include <stdio.h> 

School year..class..attendance..number..name..height..weight. 
};

int main(void) 
{
	struct student data; 
	
	data.year = 10; /* It accesses the year element *
	/ Printf("%d\n",data.year);

	return 0; 
}

10

 
#include <stdio.h> #include <string.h> 

School year..class..attendance..number..name..height..weight. 
};

int main(void)  
{
	struct student data;  
	
	strcpy(data.name,"MARIO");  
	printf("%s\n",data.name);  

	return 0;
}

MARIO

Though it explained the method of the access to each element of the structure in the preceding clause
With this, though it seems to be certainly settled to externals
An actual usage seems not to be so significant quite the same as a usual variable.

However, the structure variable can be handled for the structure as a variable.
For instance, it becomes possible to substitute in the structure variable.
The following program is an example for substitution in the structure variable.

 
#include <stdio.h> #include <string.h> 

School year..class..attendance..number..name..height..weight. 
};

int main(void)  
{
	struct student data1,data2;  
	
	/* Substitute it for data1 */ data1.year =  3;  
	data1.clas = 4;  
	data1.number = 18;  
	strcpy(data1.name,"MARIO");  
	data1.stature = 168.2;  
	data1.weight = 72.4;  
	
	data2 = data1; /* Copy the content of data1 to data2 */. 
	
	
	/* The content of data1 and data2 is 
	displayed */ Printf("data1.year =%d : data2.year =%d\n",data1.year,data2.
	year);  printf("data1.clas = %d : data2.clas = %d\n",data1.clas,data2.clas);  
	printf("data1.number = %d : data2.number = %d\n",data1.number,data2.number);  
	printf("data1.name = %s : data2.name = %s\n",data1.name,data2.name);  printf("
	data1.stature = %f : data2.stature = %f\n",data1.stature,data2.stature);  printf("
	data1.weight = %f : data2.weight = %f\n",data1.weight,data2.weight);  
	
	return 0;
}