Question

Given the following main program:

int main()
{
   int x;
   int y = 10;
   int z = 20;

   x = add(y,z);

   return 0;
}

Which function is correctly written to store the value in x?

		int add(int a, int b) {    return a+b; }
		float add(float a, float b) {    float x;    x = a + b;    return x; }
		void add(int y, int z) {    int x;    x = y + z;    return; }
		int add(y, z) {    int x;    x = y + z;    return x; }

Answer 1

Answer: Option (a) and Option (b)

Option(a):

int add(int a, int b) {    return a+b; }

It is taking both a and b values. After adding them it is returning this result to x in the main function.

Code:

#include<stdio.h>
int add(int a, int b);
int main()
{
int x;
int y = 10;
int z = 20;
x = add(y,z);
printf("The value of x will be: %d",x);
return 0;
}
int add(int a, int b)
{
return a+b;
}

Output:

Option(b):

float add(float a, float b) {    float x;    x = a + b;    return x; }

It is taking both integer values and storing them as float values. When you add them the result is float value. So it is returning a float value to the main functon. And 'x' is an integer variable , so it will cast the input and stores into it.

This processs is more hectic than the process in the option (a) , so option (a) might be the answer if you have to pick only one option.

Code:

#include<stdio.h>
float add(float a, float b);
int main()
{
int x;
int y = 10;
int z = 20;
x = add(y,z);
printf("The value of x will be: %d",x);
return 0;
}      
float add(float a, float b)
{
float x;

x = a + b;

return x;
}

Ouput:

Option (c):

void add(int y, int z) {    int x;    x = y + z;    return; }

You can observe that this code is not returning any value to the main function . After execution of this code the values computed by this peice of code will be vanished. This value will not be stored on the variable 'x' of main function. So this is an incorrect option.

Option(d):

int add(y, z) {    int x;    x = y + z;    return x; }

You can observe that it is a wrong syntax. function header "int add(x,y)" is having a wrong syntax. Type of the variable x and y are not specified which leads to an error. So this option is also incorrect.