View Compilation Error

0_0_28896936_9807.cpp: In function 'int Gauss_xor(int, int)':
0_0_28896936_9807.cpp:107:21: error: 'i' was not declared in this scope
                 for(i = 0; i < var + 1; i++)    //将第一个第col列系数非零的行换到第k行
                     ^
0_0_28896936_9807.cpp:109:22: error: 'x' was not declared in this scope
                 swap(x[max_r], x[k]);   //交换解集
                      ^
0_0_28896936_9807.cpp:117:21: error: 'x' was not declared in this scope
                     x[i] ^= x[k];
                     ^
0_0_28896936_9807.cpp:127:12: error: 'x' was not declared in this scope
         if(x[i])
            ^
0_0_28896936_9807.cpp: In function 'int main()':
0_0_28896936_9807.cpp:143:16: error: 'b' was not declared in this scope
         memset(b,0,sizeof(b));
                ^