/in/foo.cc: In function 'int main()':
/in/foo.cc:54:20: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    while(c=getchar())
                    ^
/in/foo.cc:54:4: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
    while(c=getchar())
    ^~~~~
/in/foo.cc:56:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'while'
     p=p*mod+c-'a';
     ^