Getting 1 error while building

hey! i am new to keil please help me

i am getting this error
.\Project1.axf: Error: L6218E: Undefined symbol main (referred from rtentry2.o).
Not enough information to list image symbols.
Finished: 1 information, 0 warning and 1 error messages.
".\Project1.axf" - 1 Error(s), 0 Warning(s).
Target not created

code i have pasted below

#include <stdint.h>
#include <stdbool.h>
#include "assignment.h"
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "inc/hw_gpio.h"
#include "driverlib/sysctl.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom_map.h"
#include "driverlib/gpio.h"

//*****************************************************************************
void
PortFunctionInit(void)
{ // // Enable Peripheral Clocks // MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

// // Enable pin PF2 for GPIOOutput // MAP_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);

// // Enable pin PF0 for GPIOInput //

// //First open the lock and select the bits we want to modify in the GPIO commit register. // HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY; HWREG(GPIO_PORTF_BASE + GPIO_O_CR) = 0x1;

// //Now modify the configuration of the pins that we unlocked. // MAP_GPIOPinTypeGPIOInput(GPIO_PORTF_BASE, GPIO_PIN_0);

// // Enable pin PF4 for GPIOInput // MAP_GPIOPinTypeGPIOInput(GPIO_PORTF_BASE, GPIO_PIN_4);

// // Enable pin PF3 for GPIOOutput // MAP_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_3);
}