Can enyone tell me a book to read thats eazy and for 4th grade hurry and help me PLEASE

Cprogram to find //perimeter of rectangle printf(" \n perimeter of rectangle \n"); printf(""); printf("\n enter width and length of the rectangle : "); scanf("%f%f", & width,& length); perimeter = 2 * (width + length); printf("perimeter of rectangle is: %.3f", perimeter);  

Hey and for giving me the chance to serve uthe  puzzles game can a smart person and it can grow your brain.hope l have a good day.