#include int main (void) { int nr1; int nr2; int result; char todo [9]; printf("nr1\n"); scanf("%d", &nr1); printf("nr2"); scanf("%d", &nr2); printf("what to do ? add,multiply,substract,divide"); scanf("%s", &todo); if (todo == add) { result = nr1 + nr2; printf("%d", result); } if (todo == multiply) { result = nr1 * nr2; printf("%d", result); } return 0; } errors :p c:17: error: ‘add’ undeclared (first use in this function) c:17: error: (Each undeclared identifier is reported only once c:17: error: for each function it appears in.) c:22: error: ‘multiply’ undeclared (first use in this function)