View Compilation Error

0_0_5942416_1454.cpp: In function `int main()':
0_0_5942416_1454.cpp:16: error: `scanf' undeclared (first use this function)
0_0_5942416_1454.cpp:16: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5942416_1454.cpp:19: error: `puts' undeclared (first use this function)
0_0_5942416_1454.cpp: In function `int main()':
0_0_5942416_1454.cpp:27: error: redefinition of `int main()'
0_0_5942416_1454.cpp:3: error: `int main()' previously defined here
0_0_5942416_1454.cpp:40: error: `scanf' undeclared (first use this function)
0_0_5942416_1454.cpp:43: error: `puts' undeclared (first use this function)