Defining a function outside main [closed] - c

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#include <stdio.h>
#include <math.h>
main()
{
float i;
float x,N,sum;
printf("enter x and N respectively");
scanf ("%f %f", &x, &N);
sum = 0;
for (i=1;i<=N;i++){
sum = sum + ((pow(x,i))/(fact(i)));
}
printf ("%f", sum);
}
int fact(int n){
int i,temp;
temp = 1;
for (i=1;i<=n;i++){
temp = temp*i;
return temp;
}
}
this is to print the summation of the terms accordingly. I tried defining fact inside main but there was some control flow warning and I tried the same outside this time, yet wrong answer. Any help?

Answer 1

You cannot (you are forbidden by the C99 or C11 standard) define a function (like fact) inside another one (like main).
However, some C compilers, in particular GCC accept as an extension to have nested functions.
(I don't recommend using that extension, in particular if you are newbie in C)
Of course you'll better declare
int fact(int n);
before your main and leave its definition after.
Your code is wrong (in particular, better define main as int main(int argc, char**argv) then learn perhaps about getopt and use it). Compile it with all warnings & debug info (e.g. gcc -Wall -Wextra -g homework.c -o binaryprog...) then use a debugger (e.g. gdb ./binaryprog)

Answer 2

You need to add int fact(int n); before main() function to tell the compiler that a function called fact exists or you can add the whole function definition before.

Answer 3

You have to declare fact() above of main. There are 2 ways to do it.
First way: Add int fact(int n); above of main()
Second way: Copy the whole function above main(). So it looks like:
#include <stdio.h>
#include <math.h>
int fact(int n)
{
int i,temp;
temp = 1;
for (i=1;i<=n;i++){
temp = temp*i;
return temp;
}
}
main()
{
float i;
float x,N,sum;
printf("enter x and N respectively");
scanf ("%f %f", &x, &N);
sum = 0;
for (i=1;i<=N;i++){
sum = sum + ((pow(x,i))/(fact(i)));
}
printf ("%f", sum);
}