View Compilation Error

0_0_20280442_16621.cpp:9:1: error: 'Mat' does not name a type
 Mat mat, temp1, temp2;  
 ^
0_0_20280442_16621.cpp: In function 'int main()':
0_0_20280442_16621.cpp:14:5: error: 'mod' was not declared in this scope
     mod = 2008;  
     ^
0_0_20280442_16621.cpp:18:9: error: 'mat' was not declared in this scope
         mat.clear();  
         ^
0_0_20280442_16621.cpp:44:13: error: 'temp1' was not declared in this scope
             temp1 = mat;temp2 = mat;  
             ^
0_0_20280442_16621.cpp:44:25: error: 'temp2' was not declared in this scope
             temp1 = mat;temp2 = mat;  
                         ^