View Compilation Error

0_0_34836808_12133.cpp: In function 'int main()':
0_0_34836808_12133.cpp:10:12: error: 'strcp' was not declared in this scope
   strcp(d,a);strcp(e,b);
            ^
0_0_34836808_12133.cpp:12:16: error: 'strlen' was not declared in this scope
   len1=strlen(a);
                ^
0_0_34836808_12133.cpp:25:28: error: 'f' was not declared in this scope
   printf("%s + %s = %sn",d,f,a);
                            ^