Sending structure members to a function

A member of a structure is an ordinary variable, so it can be sent to a function just like any other variable by writing structure_variable.member in the call.

• A member of a basic type (int, float, char) is sent by value: the function gets a copy, and the original does not change.
• A character array member (s.name) is sent as an array, so its address is passed (the function can change it).
• The type of the parameter must match the type of the member.

#include <stdio.h>

struct student {
    char name[20];
    int roll;
    float marks;
};

/* a single member is sent: passed by value */
void showMarks(float m)
{
    printf("Marks received in function = %.1f\n", m);
}

/* name member is a character array: its address is sent */
void showName(char n[])
{
    printf("Name received in function  = %s\n", n);
}

int main(void)
{
    struct student s = {"Ram", 10, 78.5};
    showMarks(s.marks);       /* member sent as argument */
    showName(s.name);
    showMarks(s.roll);        /* int converted to float */
    return 0;
}

Output

Marks received in function = 78.5
Name received in function  = Ram
Marks received in function = 10.0

s.marks (float) and s.name (char array) were sent to separate functions. In the last call the int member s.roll is converted to float by the compiler.