Set of instructions given to the compiler to execute set of statements until condition becomes false is called loops. The basic purpose of loop is code repetition that means same code repeted again and again. The loops in C language are used to execute a block of code or a part of the program several times.
Where need repetation of same code a number of times at that place use Loop in place of writing more than one statements. The way of the repetition will be forms a circle that's why repetition statements are called loops.