Simple Function C++ -

using namespace std; int main() {  return 0; } double c2f() {     f = value * 9 / 5 + 32;     return f; }  double k2f() {     f = (value - 273.15) * 1.8 + 32.0;     return f; }  double n2f() {     f = value * 60 / 11 + 32;     return f; } 

im having trouble calling these functions calculate temperature conversion instead of calculation within cases. program not compile after adding these functions. "error: expected ";""

you cannot declare or define functions inside function. move definitions outside of int main(){ ... }.