View Compilation Error

0_0_1379562_22749.cpp: In function `bool is(int)':
0_0_1379562_22749.cpp:8: error: `itoa' undeclared (first use this function)
0_0_1379562_22749.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1379562_22749.cpp: In function `void change(int&)':
0_0_1379562_22749.cpp:21: error: `itoa' undeclared (first use this function)