View Compilation Error

0_0_35326157_28109.cpp: In function 'int main()':
0_0_35326157_28109.cpp:5:25: error: 'scanf' was not declared in this scope
     while(~scanf("%d",&t)){
                         ^
0_0_35326157_28109.cpp:6:17: error: 'getchar' was not declared in this scope
         getchar();
                 ^
0_0_35326157_28109.cpp:8:18: error: 'gets' was not declared in this scope
         gets(word);
                  ^
0_0_35326157_28109.cpp:9:22: error: 'strlen' was not declared in this scope
         a=strlen(word);
                      ^
0_0_35326157_28109.cpp:23:19: error: 'puts' was not declared in this scope
         puts(word1);
                   ^