1.25.verification

# 1.25.verification - Reasoning About Code int deref(int*p...

This preview shows pages 1–15. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
int deref(int *p) { return *p; }
/* requires: p != NULL */ int deref(int *p) { return *p; }

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
int sum(int a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += a[i]; return total; }
/* requires: a != NULL && size(a) >= n */ int sum(int a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += a[i]; return total; }

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
/* requires: a != NULL && size(a) >= n */ int sum(int a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += a[i]; return total; }
/* requires: a != NULL && size(a) >= n */ int sum(int a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) /* 0 <= i && i < n && n <= size(a) */ total += a[i]; return total; }

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
int sumderef(int *a[], size_t n) { int total = 0, i; for (i=0; i<n; i++) total += *(a[i]); return total; }
int sumderef(int *a[], size_t n) { int total = 0, i; for (i=0; i<n; i++) total += *(a[i]); return total; } Woops! If (int)n < 0, i becomes negative, and a[i] is unsafe.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
int sumderef(int *a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += *(a[i]); return total; }
/* requires: a != NULL && size(a) >= n && ??? */ int sumderef(int *a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += *(a[i]); return total; }

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
/* requires: a != NULL && size(a) >= n && for all j in 0..n-1, a[j] != NULL */ int sumderef(int *a[], size_t n) { int total = 0; for (size_t i=0; i<n; i++) total += *(a[i]); return total; }
void *mymalloc(size_t n) { void *p = malloc(n); if (!p) { perror("malloc"); exit(1); } return p; }

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
/* ensures: retval != NULL */ void *mymalloc(size_t n) { void *p = malloc(n); if (!p) { perror("malloc"); exit(1); } return p; }
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern