#include // printf #include // EXIT_SUCCESS // This function prototype is a declaration of sumTo. // Parameter names are optional in prototypes, but recommended to make it // easier to parse, as names should provide more information about their // purpose and context. int sumTo(int); int main(int argc, char** argv) { printf("sumTo(5) is: %d\n", sumTo(5)); return EXIT_SUCCESS; } // = sum of integers from 1 to max int sumTo(int max) { int i, sum = 0; for (i = 1; i <= max; i++) { sum += i; } return sum; }