View Compilation Error

0_0_11215710_23995.cpp: In function `int cmp(thing, thing)':
0_0_11215710_23995.cpp:38: error: 'struct thing' has no member named 'cha'
0_0_11215710_23995.cpp:38: error: 'struct thing' has no member named 'cha'
0_0_11215710_23995.cpp: In function `int main()':
0_0_11215710_23995.cpp:50: error: `a' undeclared (first use this function)
0_0_11215710_23995.cpp:50: error: (Each undeclared identifier is reported only once for each function it appears in.)