I don't know that this error stands for

Itzhou17dteach-vw1: /home/2020/tzhou1/Wed Feb 19 15:42:32 EST 2020gcc-o simplecal] :c simplecalc.c simplecalc.c: In function 'main': simplecalc.c:15:16: error: switch quantity not an integer switch(argv[2]) { ANNN tzhou17@teach-vw1:/home/2020/tzhou17Wed Feb 19 15:42:33 EST 2020 #include #include int main(int argc, char* argv[]) { int ni, n2; if (argc!=4) printf("Error: usage is simplecalc "); exit(1); n1 = atoi(argv[1]); n2 = atoi(argv[3]); switch(argv[2]){ case '+': printf("%d", n1+n2); break; case '-': printf("%d", n1-n2); break; case '*': printf("%d", n1*n2); break; case '/': printf("%d", n12); 18, 16-30 23%