View Compilation Error

0_0_20384963_16862.cpp: In function 'int main()':
0_0_20384963_16862.cpp:39:27: error: 'a' was not declared in this scope
        printf("%c",str[j]+a-'A');
                           ^
0_0_20384963_16862.cpp:62:25: error: 'a' was not declared in this scope
      printf("%c",str[j]+a-'A');
                         ^