class/struct error - C2628: 'OPTIONS' followed by 'int' is illegal (did you forget a ';'?)

[h4ever]

I am trying to create struct within class OPTIONS

#include <vector>
// options generated from command line is stored here

class OPTIONS {
	struct COLORS { 
		float hmin; float smin; float vmin;
		float hmax; float smax; float vmax;
		// RGB replacecolor;
		float haddcolor; float saddcolor; float vaddcolor;
	};
	enum  ACTIONS { 
		// determines which member to work with
		// select color and replace color - paranthesis syntax
		selectMin, selectMax, replaceColor, addColor,
		regex, merge,		
		gridBoost, // Boost systems
		// Effects:
		blur, brush, kernel, extend, contract, 
		invert, levels, threshold, 
		softLight, hardLight, pinLight,  
		multiply, color, hue
	};
	struct GRID { 
		// multiplier can be used if grid dimensions are relative to image dimensions
		int w; int h; float wmultiplier; float hmultiplier;
	};
	struct MATRIX { 
		int kerneltype; int kernelw; int kernelh; float factor;
	};
	struct MERGE { 
		// multiplier can be used if grid dimensions are relative to image dimensions
		std::vector<char *> Files;
	};
	struct BLENDING {
		int softLightFactor; int hardLightFactor; int pinLightFactor;
		int multiplyFactor; int colorFactor; int hueFactor;
	};
	struct LEVELS { 
		int inputB; int inputW; int inputG;
		int outputB; int outputW; int outputG;
	};
}

int main ()
{return 0;}

I got these errors:

error C2628: 'OPTIONS' followed by 'int' is illegal (did you forget a ';'?)
error C3874: return type of 'main' should be 'int' instead of 'OPTIONS'
error C2440: 'return' : cannot convert from 'int' to 'OPTIONS'
No constructor could take the source type, or constructor overload resolution was ambiguous

The messages are to the lines:

int main ()
{return 0;}

but I am convinced that there is error in the class or struct.
If I remove main function I got error fatal error C1004: unexpected end-of-file found

Where is the error?

[wildblue]

line 58 - put semicolon after closing brace for the class

[h4ever]

Thanks