implicit declaration of function ‘strrev’ [-Wimplicit-function-declaration]

Question

I am trying to reverse a string. But when I compiled my code using gcc filename it reports the following error:

gcc itoa.c itoa.c: In function ‘main’: itoa.c:9:21: warning: implicit declaration of function ‘strrev’ [-Wimplicit-function-declaration] printf("S=%s \t \n",strrev(s)); ^

itoa.c:9:8: warning: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘int’ [-Wformat=] printf("S=%s \t \n",strrev(s)); ^

/tmp/ccK1YuDL.o: In function main': itoa.c:(.text+0x38): undefined reference tostrrev' collect2: error: ld returned 1 exit status

My src code is :

#include<stdio.h>  
#include <string.h>   
int main() {
    char s[10]="ZAkir";  
    printf("S=%s \t \n",strrev(s));  
    return 0;  
}