Issue with global variable in class - c++

Question

With the following code, it works "correctly." Meaning it creates the foot instance of WalkerJoint.
#include <WalkerJoint.h>
class WalkerLeg {
//WalkerJoint foot;
// if this is uncommented and the below is reversed it fails
public:
WalkerLeg();
void initLeg();
};
WalkerLeg::WalkerLeg(void) {
WalkerJoint foot(2,3,4,5,6);
//foot(2,3,4,5,6);
//if uncommented with above it fails
}
void initLeg() {
Serial.print("leg init\n");
}
void setup() {
Serial.begin(115200);
while (!Serial) {}
// wait for Serial comms to become ready
}
void loop() {
int bom=0;
WalkerLeg frontLeft;
bom=0;
while(bom++<100000){}
exit(0);
}
However, I need foot to be global so other methods can use it. When I move its declaration into the Class definition it gives the following error:
/Users/bin/Documents/Arduino/WalkerLeg.cpp/WalkerLeg.cpp.ino: In constructor 'WalkerLeg::WalkerLeg()':
WalkerLeg.cpp:14: error: no matching function for call to 'WalkerJoint::WalkerJoint()'
WalkerLeg::WalkerLeg(void)
^
/Users/bin/Documents/Arduino/WalkerLeg.cpp/WalkerLeg.cpp.ino:14:26: note: candidates are:
In file included from /Users/bin/Documents/Arduino/WalkerLeg.cpp/WalkerLeg.cpp.ino:1:0:
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:23:3: note: WalkerJoint::WalkerJoint(int)
WalkerJoint(int); //for using analog inputs
^
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:23:3: note: candidate expects 1 argument, 0 provided
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:22:3: note: WalkerJoint::WalkerJoint(int, int, int, int, int)
WalkerJoint(int, int, int, int, int);
^
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:22:3: note: candidate expects 5 arguments, 0 provided
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:17:7: note: constexpr WalkerJoint::WalkerJoint(const WalkerJoint&)
class WalkerJoint
^
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:17:7: note: candidate expects 1 argument, 0 provided
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:17:7: note: constexpr WalkerJoint::WalkerJoint(WalkerJoint&&)
/Users/bin/Documents/Arduino/libraries/WalkerJoint.cpp/WalkerJoint.h:17:7: note: candidate expects 1 argument, 0 provided
WalkerLeg.cpp:18: error: no match for call to '(WalkerJoint) (int, int, int, int, int)'
foot(2,3,4,5,6);
^
exit status 1
no matching function for call to 'WalkerJoint::WalkerJoint()'