What’s wrong?

Question

#include<stdio.h>
reversef(int);
int main()
{
int num,reversenum;

printf("\nEnter any number:");
scanf("%d",&num);
reversenum=reversef(num);
printf("\nAfter reverse the no is :%d",reversenum);
return 0;
}
int sum=0,rem;
reversef(int num){
if(num){
rem=num%10;
sum=sum*10+rem;
reversef(num/10);
}
else
return sum;
return sum;
}
What is wrong with this code it says error : reversef : Undeclared identifier.

Answer 1

You defined the function after you called it.

1.Define function

void func(){}

2. Use function

int main()
{
func();

return 0;
}

Answer 2

The code requires a type declaration for the return value of the reversef() function.

You only need to add int just before declaring and defining the reversef function as seen below:

//Function Declaration
int reversef(int)

and

//Function Definition
int reversef(int num) { ... }

See the code with inline comments.

https://code.sololearn.com/cjjU8E1wsa6A/

Answer 3

Corrected all the errors,

--------------------------------------------------------------

#include<stdio.h>

int reversef(int);
int sum=0,rem;

int main()
{
int num,reversenum;

printf("\nEnter any number:");
scanf("%d",&num);

reversenum=reversef(num);

printf("\nAfter reverse the no is :%d",reversenum);

return 0;
}

int reversef(int num)
{
if(num)
{
rem=num%10;
sum=sum*10+rem;
reversef(num/10);
}
else
return sum;
}

--------------------------------------------------------------