View Compilation Error

0_0_8542416_17123.cpp: In function `int main()':
0_0_8542416_17123.cpp:12: error: `s' undeclared (first use this function)
0_0_8542416_17123.cpp:12: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8542416_17123.cpp:12: error: `t' undeclared (first use this function)